[analyzer] Better fix for the "missing return" error, from Ted.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138526 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Core/CFRefCount.cpp b/lib/StaticAnalyzer/Core/CFRefCount.cpp
index 75feba4..3fa211b 100644
--- a/lib/StaticAnalyzer/Core/CFRefCount.cpp
+++ b/lib/StaticAnalyzer/Core/CFRefCount.cpp
@@ -2700,10 +2700,10 @@
       return false;
     case LangOptions::GCOnly:
       return true;
-    default:
-      llvm_unreachable("Invalid/unknown GC mode.");
-      return false;
     }
+
+    llvm_unreachable("Invalid/unknown GC mode.");
+    return false;
   }
 
   bool isARCorGCEnabled(ASTContext &Ctx) const {