core_recovery: Fix the bug in DCU/IFU test case

If BIOS is bogus so that error injection can't be executed
as expected, curent test case will fail. Fix this bug.

Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
diff --git a/cases/function/core_recovery/srar_recovery.sh b/cases/function/core_recovery/srar_recovery.sh
index f011d3d..7b13b5b 100755
--- a/cases/function/core_recovery/srar_recovery.sh
+++ b/cases/function/core_recovery/srar_recovery.sh
@@ -73,8 +73,11 @@
 echo go > trigger
 sleep 2
 rm -f trigger log
-pgrep core_recovery > /dev/null 2>&1 | xargs kill -9 > /dev/null 2>&1
-[ $? -eq 0 ] && invalid "The poisoned process can't be killed by kernel. Test fails!"
+id=`pgrep core_recovery`
+if [ X"$id" != X ]; then
+	echo $id | xargs kill -9 > /dev/null 2>&1
+	invalid "The poisoned process can't be killed by kernel automatically. Test fails!"
+fi
 
 if [ $1 == "-d" ]; then
 	echo "SRAR/DCU test passes!"