Remove the common config since its not needed

The common config currently isn't used (but will be
later, potentially in the distributed commit) so for
now remove it as its a major user of oslo.cfg which
we are trying to remove.

Part of blueprint eliminate-oslo-cfg

Change-Id: If86291511e5b304ca77505b4afd47b1663b316f5
Merge "Remove the common config since its not needed"