fix typo in LIB_PROTO_MUTATOR_HAS_NO_SANITIZE_FUZZER (#291)

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d8271e4..8735e17 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -107,7 +107,7 @@
     set(FUZZING_FLAGS "-fsanitize=fuzzer-no-link")
     set(FUZZING_FLAGS_BINARY "-fsanitize=fuzzer")
   endif()
-  if (LIB_PROTO_MUTATOR_HAS_SANITIZE_NO_FUZZER)
+  if (LIB_PROTO_MUTATOR_HAS_NO_SANITIZE_FUZZER)
     set(NO_FUZZING_FLAGS "-fno-sanitize=fuzzer")
   endif()
 endif()