fstests: support check for uuidgen utility

A recent test uses the uuidgen utility to generate UUID-based
filenames, but this package is not necessarily installed as part of
the core packages of every distro.

As such, add the UUIDGEN_PROG environment variable to the common
configuration and update the test to require the existence of
uuidgen to run.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/xfs/306

@@ -51,6 +51,7 @@ _supported_os Linux
 
 _require_scratch_nocheck	# check complains about single AG fs
 _require_xfs_io_command "fpunch"
+_require_command $UUIDGEN_PROG uuidgen
 
 rm -f $seqres.full
 
@@ -63,7 +64,7 @@ _scratch_mount
 # sufficiently populates a 64k directory block.
 mkdir $SCRATCH_MNT/src
 for i in $(seq 0 1023); do
-	touch $SCRATCH_MNT/src/`uuidgen`
+	touch $SCRATCH_MNT/src/`$UUIDGEN_PROG`
 done
 
 # precreate target dirs while we still have free space for inodes