Don't run test 56 with bogus /proc file name on client-only setup.

lustre/tests/sanity.sh

@@ -1521,7 +1521,7 @@ test_52b() {
 run_test 52b "immutable flag test (should return errors) ======="
 
 test_53() {
-        for i in /proc/fs/lustre/osc/OSC*mds1 ; do
+        for i in `ls /proc/fs/lustre/osc/OSC*mds1 2> /dev/null` ; do
                 ostname=`echo $i | cut -d _ -f 3-4 | sed -e s/_mds1//`
                 ost_last=`cat /proc/fs/lustre/obdfilter/$ostname/last_id`
                 mds_last=`cat $i/prealloc_last_id`