Put PDB parsing code into a pdb namespace.

llvm-svn: 268072
diff --git a/llvm/lib/DebugInfo/PDB/Raw/ByteStream.cpp b/llvm/lib/DebugInfo/PDB/Raw/ByteStream.cpp
index 20abe4c..d8b78ec 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/ByteStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/ByteStream.cpp
@@ -11,6 +11,7 @@
 #include "llvm/DebugInfo/PDB/Raw/StreamReader.h"
 
 using namespace llvm;
+using namespace llvm::pdb;
 
 ByteStream::ByteStream() : Owned(false) {}