v2v: Move initialization of Augeas after inspection housekeeping.

Just cleanup, it should have no effect on the way that the
conversion works.
v2v: Clean the RPM database early on (RHBZ#1143866).

If the RPM database in the source guest is corrupt, then subsequent
operations will fail randomly.

Old virt-v2v appears to have avoided this by cleaning the RPM database
very early on.  When translating the code I inadvertantly moved this
cleanup to a later stage -- in particular, after inspection of kernels
was done which requires running rpm commands.  Move this back to the
start.