Don't run 167 if killall is not installed

Test 167 will leave runaway fsstress processes around in case killall is
not installed and thus make all following tests fail.  This patch checks
for killall beeing installed and error out otherwise.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Merge of master-melb:xfs-cmds:31171a by kenmcd.

  don't run if killall is not installed.

167

@@ -13,6 +13,7 @@ owner=dgc@sgi.com
 seq=`basename $0`
 echo "QA output created by $seq"
 
+killall="/usr/bin/killall"
 here=`pwd`
 tmp=/tmp/$$
 rm -f $seq.full
@@ -43,6 +44,8 @@ workout()
 _supported_fs xfs
 _supported_os Linux
 
+[ -x $killall ] || _notrun "$killall executable not found"
+
 _setup_testdir
 _require_scratch
 _scratch_mkfs_xfs >/dev/null 2>&1