yaml::Input::mapTag(): Don't use StringRef to hold return type of std::string.

llvm-svn: 194681
diff --git a/llvm/lib/Support/YAMLTraits.cpp b/llvm/lib/Support/YAMLTraits.cpp
index 08562fc..f103ed8 100644
--- a/llvm/lib/Support/YAMLTraits.cpp
+++ b/llvm/lib/Support/YAMLTraits.cpp
@@ -83,7 +83,7 @@
 }
 
 bool Input::mapTag(StringRef Tag, bool Default) {
-  StringRef foundTag = CurrentNode->_node->getVerbatimTag();
+  std::string foundTag = CurrentNode->_node->getVerbatimTag();
   if (foundTag.empty()) {
     // If no tag found and 'Tag' is the default, say it was found.
     return Default;