For consistency, use llvm::raw_ostream in the rest of the mangle api.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125360 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ItaniumCXXABI.cpp b/lib/CodeGen/ItaniumCXXABI.cpp
index 2068c29..95654a3 100644
--- a/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/lib/CodeGen/ItaniumCXXABI.cpp
@@ -1072,7 +1072,9 @@
 
   // Create the guard variable.
   llvm::SmallString<256> GuardVName;
-  getMangleContext().mangleItaniumGuardVariable(&D, GuardVName);
+  llvm::raw_svector_ostream Out(GuardVName);
+  getMangleContext().mangleItaniumGuardVariable(&D, Out);
+  Out.flush();
 
   // Just absorb linkage and visibility from the variable.
   llvm::GlobalVariable *GuardVariable =