Remove unnecessary default cases in switches over enums.

This allows -Wswitch-enum to find switches that need updating when these enums are modified.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148281 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/LangStandards.cpp b/lib/Frontend/LangStandards.cpp
index abb521b..f86a574 100644
--- a/lib/Frontend/LangStandards.cpp
+++ b/lib/Frontend/LangStandards.cpp
@@ -19,14 +19,13 @@
 
 const LangStandard &LangStandard::getLangStandardForKind(Kind K) {
   switch (K) {
-  default:
-    llvm_unreachable("Invalid language kind!");
   case lang_unspecified:
     llvm::report_fatal_error("getLangStandardForKind() on unspecified kind");
 #define LANGSTANDARD(id, name, desc, features) \
     case lang_##id: return Lang_##id;
 #include "clang/Frontend/LangStandards.def"
   }
+  llvm_unreachable("Invalid language kind!");
 }
 
 const LangStandard *LangStandard::getLangStandardForName(StringRef Name) {