Add build generated *.py[oc] to .gitignore

Related to:
http://review.gluster.org/8237

Change-Id: I8f888f0363c4358026ad17b2dc288014f7c51466
BUG: 1119328
Signed-off-by: Prashanth Pai <ppai@redhat.com>
Reviewed-on: http://review.gluster.org/8311
Reviewed-by: Humble Devassy Chirammal <humble.devassy@gmail.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>