vgimportclone: fix non-duplicate PV with non-unique basevgname arg

vgimportclone: fix non-duplicate PV with non-unique basevgname arg

Fix hang of vgimportclone command when:
the PV(s) being imported are not actually clones/duplicates, and
the -n vgname arg is the same as the current vgname.

(Not the intended use of the command, but it should still work.)

In this case, the old and new vgnames ended up being the same, when
the code expected they would be different.  A file lock on both the
old and new vgnames is used, so when both flocks are on the same
file, the second blocks indefinitely.

Fix the new vgname to be the old name plus a numeric suffix, which
is the expected result.