Use SmallVectorImpl::reverse_iterator instead of SmallVector to avoid specifying the vector size.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185784 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Module.cpp b/lib/Basic/Module.cpp
index 8ac098c..7b1fe8f 100644
--- a/lib/Basic/Module.cpp
+++ b/lib/Basic/Module.cpp
@@ -111,8 +111,8 @@
     Names.push_back(M->Name);
   
   std::string Result;
-  for (SmallVector<StringRef, 2>::reverse_iterator I = Names.rbegin(),
-                                                IEnd = Names.rend();
+  for (SmallVectorImpl<StringRef>::reverse_iterator I = Names.rbegin(),
+                                                 IEnd = Names.rend();
        I != IEnd; ++I) {
     if (!Result.empty())
       Result += '.';