Move yaml::Stream's dtor out of line so it can see Scanner's dtor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154004 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/YAMLParser.h

@@ -78,6 +78,7 @@ std::string escape(StringRef Input);
 class Stream {
 public:
   Stream(StringRef Input, SourceMgr &);
+  ~Stream();
 
   document_iterator begin();
   document_iterator end();