Write and read more complex git sha info

Instead of encoding the git sha into the version string, add it to
a metadata file. This will allow us to get out of the business of
arguing with pip and setuptools about version info. In order to make
this really nice, provide a command line utility called "pbr" that has
subcommands to print out the metadata that we're now including in the
egg-info dir.

Change-Id: I35a1489c9ab637769218d1e6a26d1115a52a7051
Stop including git sha in version strings

We include it in pbr.json now. Including it is contentious in the world
of python, and it's up for debate as to whether or not it provides
value.

Change-Id: Ie2ca34f59e9b42a3126c95edf36640fef32feed8
Merge tag '0.10.3' into master

Releasing 0.10.3

Change-Id: If8dd160585172a09064413305123eb2d1079d5b6