Fix broken test.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@52232 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/string-init.c b/test/CodeGen/string-init.c
index c703c62..f3ad4c5 100644
--- a/test/CodeGen/string-init.c
+++ b/test/CodeGen/string-init.c
@@ -1,4 +1,4 @@
-// RUN: clang -emit-llvm %s -o - | not grep "[5 x i8]" &&
+// RUN: clang -emit-llvm %s -o - | not grep -F "[5 x i8]" &&
 // RUN: clang -emit-llvm %s -o - | not grep "store"
 
 void test(void) {