[DOCKER] Revert git shallow clone change. (#2841)
[DOCKER] Revert git shallow clone change. (#2841)

This patch reverts one of my earlier patches (squashed in #2710) to
reduce bandwidth requirements of git clone, in this particular case we
are checking out a specific hash rather than a tag or branch name. The
--branch option to git clone permits tags or branches but does not
permit a specific hash.
dmlc/tvm,sxjscience/tvm,Huyuwei/tvm,tqchen/tvm,Huyuwei/tvm,tqchen/tvm,Huyuwei/tvm,Laurawly/tvm-1,Huyuwei/tvm,dmlc/tvm,sxjscience/tvm,dmlc/tvm,Laurawly/tvm-1,Huyuwei/tvm,tqchen/tvm,tqchen/tvm,dmlc/tvm,dmlc/tvm,sxjscience/tvm,Huyuwei/tvm,Laurawly/tvm-1,Laurawly/tvm-1,sxjscience/tvm,dmlc/tvm,Laurawly/tvm-1,tqchen/tvm,tqchen/tvm,Laurawly/tvm-1,sxjscience/tvm,tqchen/tvm,dmlc/tvm,tqchen/tvm,Laurawly/tvm-1,Huyuwei/tvm,sxjscience/tvm,dmlc/tvm,Laurawly/tvm-1,sxjscience/tvm,Laurawly/tvm-1,Huyuwei/tvm,tqchen/tvm,dmlc/tvm,Laurawly/tvm-1,sxjscience/tvm,sxjscience/tvm,Huyuwei/tvm,tqchen/tvm