Begin moving some of the common code to a shared base

To enable the addition of a new lockfile impl that
has some of the similar functionality as the existing impls
in pylockfile we need to break out what will be shared and
what will not be shared by the existing impls and the soon
to be added new impl.

Change-Id: I3fddfb05b78657ebed1449f0389004061e7e7082
Merge "Begin moving some of the common code to a shared base"