[PATCH 0/2 V3] allow UUID changes on V5/CRC filesystems

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

Final version?  This has been through some degree of testing, by changing
the UUID after a CRC mkfs, and re-setting it in between two xfs_repair runs
before and after each test in the testsuite.

I still probably owe some xfstests testcases.

This is rebased onto the new xfsprogs libxfs rebase, and I removed the noise
if a user asks to "restore" the UUID on a filesystem which doesn't need it -
it just does nothing, and succeeds silently.

Thanks,
-Eric