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