Fix pbr and hacking requirements.

There were pbr version conflicts due to the old version of hacking that
we had pinned here. Pin newer pbr and hacking to unstick the tests for
jeepyb and to make it clear why this happens in the future.

Change-Id: I75a1f6f956880f2bec8a182782b17e5055315e75
Determine yaml format when loading yaml configs.

The yaml document was split into a yaml file and a .ini file instead of
two yaml docs in one file. Determine which format is in use wherever the
yaml document is read to ensure the correct configs are read by jeepyb.

Closes-bug: 1276180
Change-Id: Ib66cbec223d6aaa9cf06a5b0b002e37502a6e95a
Override project settings in ini file

We manage project settings in 2 files, projects.ini and projects.yaml file. If
ini file is present, read defaults from this file and parse yaml using new
convention.

Change-Id: I5bc2e81388420ce03d5379b8d75063481887243b