Spell empty StringRef correctly (0 is a null StringRef, which is not the same).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@87011 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Sema/CodeCompleteConsumer.h

@@ -106,7 +106,7 @@ public:
     
     Chunk() : Kind(CK_Text), Text(0) { }
     
-    Chunk(ChunkKind Kind, llvm::StringRef Text = 0);
+    Chunk(ChunkKind Kind, llvm::StringRef Text = "");
     
     /// \brief Create a new text chunk.
     static Chunk CreateText(const char *Text);

lib/Sema/CodeCompleteConsumer.cpp

@@ -28,7 +28,7 @@ using namespace clang;
 // Code completion string implementation
 //===----------------------------------------------------------------------===//
 CodeCompletionString::Chunk::Chunk(ChunkKind Kind, llvm::StringRef Text) 
-  : Kind(Kind), Text(0)
+  : Kind(Kind), Text("")
 {
   switch (Kind) {
   case CK_TypedText: