QA test updates for external log/rt devices.

Make sure we don't run this test with mutually exclusive mkfs options.

016

@@ -80,7 +80,10 @@ _init()
     echo "*** mkfs"
     force_opts="-dsize=50m -lsize=2097152"
     echo mkfs_xfs $force_opts $SCRATCH_DEV >>$seq.full
-    _scratch_mkfs_xfs $force_opts | _filter_mkfs >/dev/null 2>$tmp.mkfs
+    _scratch_mkfs_xfs $force_opts >$tmp.mkfs0 2>&1
+    [ $? -ne 0 ] && \
+        _notrun "Cannot mkfs for this test using MKFS_OPTIONS specified"
+    _filter_mkfs <$tmp.mkfs0 >/dev/null 2>$tmp.mkfs
     source $tmp.mkfs
 }