Fixed CMake build compile error; don't compile GMock with cxx11 flag.
Fixed CMake build compile error; don't compile GMock with cxx11 flag.

Right now if you try to compile GMock a non-Windows platform using the
CMake build system, it will error out. The problem seems to be the CXX11
flag.

This commit will solve this problem by removing that flag.

Review: https://reviews.apache.org/r/37370

reneploetz/mesos,jpeach/mesos,Aman-Jain-14/customizedMesos,verizonlabs/mesos,Gilbert88/mesos,dforsyth/mesos,gsantovena/mesos,zmalik/mesos,craimbert/mesos,jpeach/mesos,abudnik/mesos,gsantovena/mesos,gsantovena/mesos,zmalik/mesos,asamerh4/mesos,kaysoky/mesos,Gilbert88/mesos,andschwa/mesos,kaysoky/mesos,neilconway/mesos,asamerh4/mesos,Gilbert88/mesos,neilconway/mesos,zmalik/mesos,jpeach/mesos,asamerh4/mesos,reneploetz/mesos,kaysoky/mesos,neilconway/mesos,andschwa/mesos,kaysoky/mesos,jpeach/mesos,chhsia0/mesos,dforsyth/mesos,jpeach/mesos,reneploetz/mesos,chhsia0/mesos,Gilbert88/mesos,abudnik/mesos,zmalik/mesos,zmalik/mesos,andschwa/mesos,neilconway/mesos,andschwa/mesos,yuquanshan/customizedMesos,chhsia0/mesos,gsantovena/mesos,dforsyth/mesos,gsantovena/mesos,yuquanshan/customizedMesos,verizonlabs/mesos,kaysoky/mesos,zmalik/mesos,abudnik/mesos,Aman-Jain-14/customizedMesos,chhsia0/mesos,craimbert/mesos,craimbert/mesos,neilconway/mesos,chhsia0/mesos,kaysoky/mesos,verizonlabs/mesos,craimbert/mesos,Aman-Jain-14/customizedMesos,dforsyth/mesos,craimbert/mesos,zmalik/mesos,dforsyth/mesos,Aman-Jain-14/customizedMesos,dforsyth/mesos,dforsyth/mesos,craimbert/mesos,craimbert/mesos,abudnik/mesos,asamerh4/mesos,asamerh4/mesos,verizonlabs/mesos,yuquanshan/customizedMesos,Aman-Jain-14/customizedMesos,andschwa/mesos,kaysoky/mesos,asamerh4/mesos,gsantovena/mesos,Gilbert88/mesos,chhsia0/mesos,reneploetz/mesos,jpeach/mesos,Gilbert88/mesos,andschwa/mesos,reneploetz/mesos,chhsia0/mesos,Gilbert88/mesos,reneploetz/mesos,yuquanshan/customizedMesos,abudnik/mesos,yuquanshan/customizedMesos,asamerh4/mesos,yuquanshan/customizedMesos,neilconway/mesos,verizonlabs/mesos,verizonlabs/mesos,Aman-Jain-14/customizedMesos,reneploetz/mesos,Aman-Jain-14/customizedMesos,abudnik/mesos,jpeach/mesos,gsantovena/mesos,abudnik/mesos,yuquanshan/customizedMesos,andschwa/mesos,neilconway/mesos,verizonlabs/mesos