Support "generic" filesystem type

Create a new "generic" _supported_fs type for tests
which are not really filesystem-specific.  "generic"
tests do expect that acl & attr are supported though.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>

common.rc

@@ -546,7 +546,7 @@ _supported_fs()
 {
     for f
     do
-	if [ "$f" = "$FSTYP" ]
+	if [ "$f" = "$FSTYP" -o "$f" = "generic" ]
 	then
 	    return
 	fi