Update .gitignore for cmake generated file
Update .gitignore for cmake generated file

While running cmake in Linux:
```
tensorflow/tools/ci_build/ci_build.sh CMAKE tensorflow/tools/ci_build/builds/cmake.sh
```

the following file is generated and left out:
```
ubuntu@ubuntu:~/tensorflow$ git status
On branch master
Your branch is up-to-date with 'origin/master'.
Untracked files:
  (use "git add <file>..." to include in what will be committed)

        estimator_api_init_files_list.txt

nothing added to commit but untracked files present (use "git add" to track)
```

This fix add `/estimator_api_init_files_list.txt`
in gitignore so that it will not be picked by `git add -A`.

Signed-off-by: Yong Tang <765086fe2e0c1f980161f127fec596800f327f62@outlook.com>

ppwwyyxx/tensorflow,karllessard/tensorflow,Bismarrck/tensorflow,freedomtan/tensorflow,petewarden/tensorflow,aselle/tensorflow,gautam1858/tensorflow,tensorflow/tensorflow,jbedorf/tensorflow,hfp/tensorflow-xsmm,dongjoon-hyun/tensorflow,kevin-coder/tensorflow-fork,DavidNorman/tensorflow,dancingdan/tensorflow,asimshankar/tensorflow,gunan/tensorflow,renyi533/tensorflow,xodus7/tensorflow,DavidNorman/tensorflow,cxxgtxy/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,jendap/tensorflow,ZhangXinNan/tensorflow,frreiss/tensorflow-fred,frreiss/tensorflow-fred,jbedorf/tensorflow,tensorflow/tensorflow-pywrap_saved_model,tensorflow/tensorflow-pywrap_tf_optimizer,cxxgtxy/tensorflow,davidzchen/tensorflow,seanli9jan/tensorflow,theflofly/tensorflow,ageron/tensorflow,tensorflow/tensorflow-pywrap_saved_model,asimshankar/tensorflow,manipopopo/tensorflow,Intel-Corporation/tensorflow,petewarden/tensorflow,ZhangXinNan/tensorflow,AnishShah/tensorflow,annarev/tensorflow,gautam1858/tensorflow,adit-chandra/tensorflow,adit-chandra/tensorflow,apark263/tensorflow,adit-chandra/tensorflow,jendap/tensorflow,jalexvig/tensorflow,petewarden/tensorflow,adit-chandra/tensorflow,alsrgv/tensorflow,adit-chandra/tensorflow,tensorflow/tensorflow-pywrap_saved_model,davidzchen/tensorflow,kevin-coder/tensorflow-fork,yongtang/tensorflow,ageron/tensorflow,Bismarrck/tensorflow,Bismarrck/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,asimshankar/tensorflow,cxxgtxy/tensorflow,sarvex/tensorflow,frreiss/tensorflow-fred,xodus7/tensorflow,dancingdan/tensorflow,adit-chandra/tensorflow,petewarden/tensorflow,jalexvig/tensorflow,freedomtan/tensorflow,kevin-coder/tensorflow-fork,frreiss/tensorflow-fred,petewarden/tensorflow,jbedorf/tensorflow,petewarden/tensorflow,snnn/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,chemelnucfin/tensorflow,Intel-Corporation/tensorflow,ZhangXinNan/tensorflow,freedomtan/tensorflow,aam-at/tensorflow,kobejean/tensorflow,apark263/tensorflow,dancingdan/tensorflow,gautam1858/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,hfp/tensorflow-xsmm,hehongliang/tensorflow,hfp/tensorflow-xsmm,girving/tensorflow,frreiss/tensorflow-fred,karllessard/tensorflow,manipopopo/tensorflow,Bismarrck/tensorflow,jbedorf/tensorflow,frreiss/tensorflow-fred,AnishShah/tensorflow,dongjoon-hyun/tensorflow,aldian/tensorflow,ghchinoy/tensorflow,arborh/tensorflow,adit-chandra/tensorflow,alshedivat/tensorflow,apark263/tensorflow,arborh/tensorflow,Intel-tensorflow/tensorflow,gautam1858/tensorflow,Bismarrck/tensorflow,xzturn/tensorflow,yongtang/tensorflow,manipopopo/tensorflow,apark263/tensorflow,xzturn/tensorflow,ZhangXinNan/tensorflow,brchiu/tensorflow,jhseu/tensorflow,Intel-Corporation/tensorflow,girving/tensorflow,seanli9jan/tensorflow,apark263/tensorflow,apark263/tensorflow,kevin-coder/tensorflow-fork,arborh/tensorflow,ZhangXinNan/tensorflow,dancingdan/tensorflow,annarev/tensorflow,aldian/tensorflow,sarvex/tensorflow,sarvex/tensorflow,alshedivat/tensorflow,paolodedios/tensorflow,Intel-Corporation/tensorflow,theflofly/tensorflow,arborh/tensorflow,Bismarrck/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,aldian/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow-pywrap_saved_model,tensorflow/tensorflow-pywrap_saved_model,xodus7/tensorflow,freedomtan/tensorflow,apark263/tensorflow,jhseu/tensorflow,hehongliang/tensorflow,Intel-tensorflow/tensorflow,xzturn/tensorflow,kobejean/tensorflow,gunan/tensorflow,ghchinoy/tensorflow,petewarden/tensorflow,ageron/tensorflow,freedomtan/tensorflow,asimshankar/tensorflow,gautam1858/tensorflow,jhseu/tensorflow,seanli9jan/tensorflow,ppwwyyxx/tensorflow,ppwwyyxx/tensorflow,hehongliang/tensorflow,ppwwyyxx/tensorflow,arborh/tensorflow,karllessard/tensorflow,tensorflow/tensorflow,brchiu/tensorflow,sarvex/tensorflow,gautam1858/tensorflow,manipopopo/tensorflow,tensorflow/tensorflow,cxxgtxy/tensorflow,DavidNorman/tensorflow,jbedorf/tensorflow,petewarden/tensorflow,jendap/tensorflow,sarvex/tensorflow,karllessard/tensorflow,seanli9jan/tensorflow,seanli9jan/tensorflow,paolodedios/tensorflow,adit-chandra/tensorflow,jalexvig/tensorflow,ageron/tensorflow,alsrgv/tensorflow,alsrgv/tensorflow,jalexvig/tensorflow,snnn/tensorflow,ppwwyyxx/tensorflow,ppwwyyxx/tensorflow,kobejean/tensorflow,xodus7/tensorflow,davidzchen/tensorflow,kobejean/tensorflow,aldian/tensorflow,dongjoon-hyun/tensorflow,dancingdan/tensorflow,karllessard/tensorflow,gunan/tensorflow,ppwwyyxx/tensorflow,dancingdan/tensorflow,freedomtan/tensorflow,jhseu/tensorflow,jalexvig/tensorflow,tensorflow/tensorflow-pywrap_saved_model,paolodedios/tensorflow,chemelnucfin/tensorflow,alshedivat/tensorflow,seanli9jan/tensorflow,freedomtan/tensorflow,arborh/tensorflow,gautam1858/tensorflow,jendap/tensorflow,ageron/tensorflow,Bismarrck/tensorflow,ghchinoy/tensorflow,jendap/tensorflow,tensorflow/tensorflow,ghchinoy/tensorflow,Intel-tensorflow/tensorflow,gunan/tensorflow,chemelnucfin/tensorflow,freedomtan/tensorflow,tensorflow/tensorflow,manipopopo/tensorflow,snnn/tensorflow,asimshankar/tensorflow,alshedivat/tensorflow,karllessard/tensorflow,girving/tensorflow,renyi533/tensorflow,alshedivat/tensorflow,yongtang/tensorflow,davidzchen/tensorflow,kevin-coder/tensorflow-fork,arborh/tensorflow,chemelnucfin/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,aam-at/tensorflow,alsrgv/tensorflow,DavidNorman/tensorflow,jendap/tensorflow,dancingdan/tensorflow,gautam1858/tensorflow,chemelnucfin/tensorflow,renyi533/tensorflow,karllessard/tensorflow,jbedorf/tensorflow,aselle/tensorflow,DavidNorman/tensorflow,kobejean/tensorflow,alsrgv/tensorflow,girving/tensorflow,DavidNorman/tensorflow,brchiu/tensorflow,apark263/tensorflow,aselle/tensorflow,girving/tensorflow,gunan/tensorflow,adit-chandra/tensorflow,manipopopo/tensorflow,ZhangXinNan/tensorflow,girving/tensorflow,frreiss/tensorflow-fred,gautam1858/tensorflow,paolodedios/tensorflow,petewarden/tensorflow,frreiss/tensorflow-fred,tensorflow/tensorflow-experimental_link_static_libraries_once,gunan/tensorflow,jhseu/tensorflow,AnishShah/tensorflow,apark263/tensorflow,xodus7/tensorflow,snnn/tensorflow,yongtang/tensorflow,aselle/tensorflow,dongjoon-hyun/tensorflow,theflofly/tensorflow,jbedorf/tensorflow,xzturn/tensorflow,gunan/tensorflow,davidzchen/tensorflow,hfp/tensorflow-xsmm,davidzchen/tensorflow,kobejean/tensorflow,ppwwyyxx/tensorflow,jhseu/tensorflow,seanli9jan/tensorflow,xzturn/tensorflow,seanli9jan/tensorflow,ghchinoy/tensorflow,kobejean/tensorflow,seanli9jan/tensorflow,annarev/tensorflow,frreiss/tensorflow-fred,jendap/tensorflow,aselle/tensorflow,cxxgtxy/tensorflow,jendap/tensorflow,AnishShah/tensorflow,dongjoon-hyun/tensorflow,kobejean/tensorflow,DavidNorman/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,Intel-tensorflow/tensorflow,xodus7/tensorflow,tensorflow/tensorflow-pywrap_saved_model,freedomtan/tensorflow,renyi533/tensorflow,manipopopo/tensorflow,Intel-tensorflow/tensorflow,jhseu/tensorflow,yongtang/tensorflow,jalexvig/tensorflow,freedomtan/tensorflow,petewarden/tensorflow,jalexvig/tensorflow,theflofly/tensorflow,arborh/tensorflow,karllessard/tensorflow,adit-chandra/tensorflow,aselle/tensorflow,cxxgtxy/tensorflow,Bismarrck/tensorflow,yongtang/tensorflow,chemelnucfin/tensorflow,chemelnucfin/tensorflow,davidzchen/tensorflow,dongjoon-hyun/tensorflow,xzturn/tensorflow,brchiu/tensorflow,annarev/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,ghchinoy/tensorflow,snnn/tensorflow,annarev/tensorflow,alsrgv/tensorflow,asimshankar/tensorflow,girving/tensorflow,brchiu/tensorflow,Intel-tensorflow/tensorflow,hfp/tensorflow-xsmm,theflofly/tensorflow,theflofly/tensorflow,gunan/tensorflow,paolodedios/tensorflow,AnishShah/tensorflow,AnishShah/tensorflow,jendap/tensorflow,paolodedios/tensorflow,AnishShah/tensorflow,jalexvig/tensorflow,annarev/tensorflow,dancingdan/tensorflow,annarev/tensorflow,gunan/tensorflow,jalexvig/tensorflow,theflofly/tensorflow,davidzchen/tensorflow,ppwwyyxx/tensorflow,kevin-coder/tensorflow-fork,gautam1858/tensorflow,xzturn/tensorflow,frreiss/tensorflow-fred,hfp/tensorflow-xsmm,annarev/tensorflow,aldian/tensorflow,aam-at/tensorflow,hfp/tensorflow-xsmm,aam-at/tensorflow,alshedivat/tensorflow,AnishShah/tensorflow,Intel-tensorflow/tensorflow,ZhangXinNan/tensorflow,brchiu/tensorflow,ppwwyyxx/tensorflow,arborh/tensorflow,ZhangXinNan/tensorflow,alsrgv/tensorflow,manipopopo/tensorflow,girving/tensorflow,renyi533/tensorflow,tensorflow/tensorflow-pywrap_saved_model,jhseu/tensorflow,davidzchen/tensorflow,aselle/tensorflow,aldian/tensorflow,snnn/tensorflow,Intel-Corporation/tensorflow,Intel-tensorflow/tensorflow,asimshankar/tensorflow,kevin-coder/tensorflow-fork,tensorflow/tensorflow,xodus7/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,ageron/tensorflow,snnn/tensorflow,kevin-coder/tensorflow-fork,yongtang/tensorflow,chemelnucfin/tensorflow,ageron/tensorflow,Intel-Corporation/tensorflow,karllessard/tensorflow,snnn/tensorflow,yongtang/tensorflow,aam-at/tensorflow,aselle/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,paolodedios/tensorflow,theflofly/tensorflow,alshedivat/tensorflow,renyi533/tensorflow,apark263/tensorflow,dongjoon-hyun/tensorflow,hehongliang/tensorflow,brchiu/tensorflow,jbedorf/tensorflow,ppwwyyxx/tensorflow,ZhangXinNan/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,arborh/tensorflow,tensorflow/tensorflow-pywrap_saved_model,DavidNorman/tensorflow,frreiss/tensorflow-fred,brchiu/tensorflow,renyi533/tensorflow,aam-at/tensorflow,hehongliang/tensorflow,xzturn/tensorflow,freedomtan/tensorflow,paolodedios/tensorflow,hehongliang/tensorflow,davidzchen/tensorflow,arborh/tensorflow,kobejean/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,aam-at/tensorflow,kevin-coder/tensorflow-fork,cxxgtxy/tensorflow,paolodedios/tensorflow,chemelnucfin/tensorflow,aam-at/tensorflow,gunan/tensorflow,alsrgv/tensorflow,girving/tensorflow,renyi533/tensorflow,chemelnucfin/tensorflow,brchiu/tensorflow,asimshankar/tensorflow,tensorflow/tensorflow,asimshankar/tensorflow,renyi533/tensorflow,xzturn/tensorflow,ghchinoy/tensorflow,ghchinoy/tensorflow,Intel-tensorflow/tensorflow,alsrgv/tensorflow,gautam1858/tensorflow,petewarden/tensorflow,aselle/tensorflow,renyi533/tensorflow,manipopopo/tensorflow,aldian/tensorflow,brchiu/tensorflow,chemelnucfin/tensorflow,manipopopo/tensorflow,jhseu/tensorflow,jalexvig/tensorflow,alsrgv/tensorflow,dancingdan/tensorflow,ageron/tensorflow,petewarden/tensorflow,gunan/tensorflow,tensorflow/tensorflow,paolodedios/tensorflow,annarev/tensorflow,xodus7/tensorflow,chemelnucfin/tensorflow,sarvex/tensorflow,arborh/tensorflow,jbedorf/tensorflow,jhseu/tensorflow,tensorflow/tensorflow,adit-chandra/tensorflow,renyi533/tensorflow,tensorflow/tensorflow,yongtang/tensorflow,cxxgtxy/tensorflow,freedomtan/tensorflow,kobejean/tensorflow,snnn/tensorflow,snnn/tensorflow,xodus7/tensorflow,seanli9jan/tensorflow,jhseu/tensorflow,xodus7/tensorflow,tensorflow/tensorflow,aselle/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,theflofly/tensorflow,gunan/tensorflow,alshedivat/tensorflow,theflofly/tensorflow,asimshankar/tensorflow,girving/tensorflow,kevin-coder/tensorflow-fork,apark263/tensorflow,Intel-tensorflow/tensorflow,Bismarrck/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,karllessard/tensorflow,snnn/tensorflow,kevin-coder/tensorflow-fork,jendap/tensorflow,jbedorf/tensorflow,jbedorf/tensorflow,aam-at/tensorflow,girving/tensorflow,sarvex/tensorflow,sarvex/tensorflow,davidzchen/tensorflow,manipopopo/tensorflow,aam-at/tensorflow,ghchinoy/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,kobejean/tensorflow,dongjoon-hyun/tensorflow,ghchinoy/tensorflow,frreiss/tensorflow-fred,paolodedios/tensorflow,ageron/tensorflow,ZhangXinNan/tensorflow,aldian/tensorflow,renyi533/tensorflow,aam-at/tensorflow,DavidNorman/tensorflow,asimshankar/tensorflow,aam-at/tensorflow,tensorflow/tensorflow-experimental_link_static_libraries_once,jendap/tensorflow,seanli9jan/tensorflow,dongjoon-hyun/tensorflow,adit-chandra/tensorflow,hehongliang/tensorflow,alshedivat/tensorflow,karllessard/tensorflow,theflofly/tensorflow,AnishShah/tensorflow,dancingdan/tensorflow,DavidNorman/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,tensorflow/tensorflow-experimental_link_static_libraries_once,jbedorf/tensorflow,hfp/tensorflow-xsmm,Intel-Corporation/tensorflow,DavidNorman/tensorflow,alshedivat/tensorflow,AnishShah/tensorflow,xodus7/tensorflow,hfp/tensorflow-xsmm,annarev/tensorflow,alsrgv/tensorflow,jalexvig/tensorflow,Bismarrck/tensorflow,Intel-tensorflow/tensorflow,dongjoon-hyun/tensorflow,ghchinoy/tensorflow,davidzchen/tensorflow,brchiu/tensorflow,tensorflow/tensorflow-pywrap_saved_model,xzturn/tensorflow,tensorflow/tensorflow-pywrap_tf_optimizer,Intel-Corporation/tensorflow,theflofly/tensorflow,ppwwyyxx/tensorflow,dongjoon-hyun/tensorflow,ageron/tensorflow,yongtang/tensorflow,hfp/tensorflow-xsmm,jhseu/tensorflow,AnishShah/tensorflow,alshedivat/tensorflow,gautam1858/tensorflow,aselle/tensorflow,yongtang/tensorflow,ageron/tensorflow,dancingdan/tensorflow,ghchinoy/tensorflow,hfp/tensorflow-xsmm,xzturn/tensorflow,DavidNorman/tensorflow,alsrgv/tensorflow,ageron/tensorflow,Bismarrck/tensorflow,xzturn/tensorflow,tensorflow/tensorflow-pywrap_saved_model,ZhangXinNan/tensorflow,annarev/tensorflow