xfstests: use blkid raw mode

blkid without options usually gets no probe results at all just after
creating a filesystem.  This problem is due to the cache that blkid
uses in it's default mode, and is unlikely to get fixed.  Use the -p
option to bypass the cache layer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>

common

@@ -47,7 +47,7 @@ rm -f $tmp.list $tmp.tmp $tmp.sed
 # Autodetect fs type based on what's on $TEST_DEV
 if [ "$HOSTOS" == "Linux" ]
 then
-    export FSTYP=`blkid -s TYPE -o value $TEST_DEV`
+    export FSTYP=`blkid -p -s TYPE -o value $TEST_DEV`
 else
     export FSTYP=xfs
 fi