Rename find_pv_in_dev to find_pvheader_in_dev
Rename find_pv_in_dev to find_pvheader_in_dev

Because that's what it actually is doing.

Signed-off-by: Andy Grover <b7d524d2f5cc5aebadb6b92b08d3ab26911cde33@redhat.com>

agrover/melvin