Teach raw_ostream to accept SmallString.

Saves adding .str() call to any raw_ostream << SmallString usage
and a small step towards making .str() consistent in the ADTs by
removing one of the SmallString::str() use cases, discussion at

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20141013/240026.html

I'll update the Phabricator patch http://reviews.llvm.org/D6372
for review of the Twine SmallString support, it's more complex
than this one.

llvm-svn: 231763
diff --git a/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp b/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp
index 6812b11..621718e 100644
--- a/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp
+++ b/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp
@@ -735,7 +735,7 @@
   SmallString<128> P;
   int FD;
   llvm::sys::fs::createTemporaryFile("llvm_ubi", "", FD, P);
-  llvm::errs() << "Writing '" << P.str() << "'.\n";
+  llvm::errs() << "Writing '" << P << "'.\n";
 
   auto Stream = llvm::make_unique<llvm::raw_fd_ostream>(FD, true);