package_rpm: Ensure PV manipulations are correct

The previous change to this function fixed one manipuation at
the expense of the other, depending on ow expanded the versioned
dependency string was when the AUTOINC substitution was made.

This update ensures we cover both cases and ensures the classextended
version works as as well as the normal case.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>