DAFS: Put back volumes we get in FSSYNC handlers

DAFS: Put back volumes we get in FSSYNC handlers

fssync-server.c has a few issues with not properly VPutVolume_r'ing
volumes that were VGetVolume_r'd. The most important of these was that
the handler for FSYNC_VOL_MOVE can put back a volume it did not get,
when DAFS is enabled.

Fix that, and another erroneous edge case in the FSYNC_VOL_QUERY_HDR
handler when DAFS is not enabled.

Reviewed-on: http://gerrit.openafs.org/477
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>