btrfs-progs: tests: Check for metadata_uuid feature in misc-tests/034-metadata-uuid

Instead of checking the kernel version, explicitly check for the
presence of metadata_uuid file in sysfs. This allows the test to be run
on older kernels that might have this feature backported.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

tests/misc-tests/034-metadata-uuid/test.sh

@@ -10,8 +10,8 @@ check_prereq btrfs-image
 setup_root_helper
 prepare_test_dev
 
-if ! check_min_kernel_version 5.0; then
-	_not_run "kernel too old, METADATA_UUID support needed"
+if [ ! -f /sys/fs/btrfs/features/metadata_uuid ] ; then
+	_not_run "METADATA_UUID feature not supported"
 fi
 
 read_fsid() {