btrfs-progs: tests: don't show grep output when checking stream version

The test misc/058 does not properly filter out the output due to -s that
only ignores non-existent files and was there due to previous changes.
We need to use -q.

Signed-off-by: David Sterba <dsterba@suse.com>

tests/misc-tests/053-receive-write-encoded/test.sh

@@ -12,7 +12,7 @@ setup_root_helper
 prepare_test_dev
 
 if ! [ -f "/sys/fs/btrfs/features/send_stream_version" ] ||
-   grep -s '1$' "/sys/fs/btrfs/features/send_stream_version"; then
+   grep -q '1$' "/sys/fs/btrfs/features/send_stream_version"; then
 	_not_run "kernel does not support send stream >1"
 	exit
 fi