Include sha hash in python variable __version__

It is necessary to symlink in files from .git/ in order to make
bazel aware of changes to the current head. As it is this is not
completely reliable when git repositories are in a dirty index
state. First class support for bazel git a reported bug but
not a high priority.

./configure sets up the symlinks by calling the gen_git_source.py
a bazel genrule calls gen_git_source.py to generate version_info.cc

Also changed cmake and make to build this properly.
Change: 132328009