Move pdb code into pdb namespace.

llvm-svn: 268544
diff --git a/llvm/lib/DebugInfo/PDB/PDBContext.cpp b/llvm/lib/DebugInfo/PDB/PDBContext.cpp
index 73c5616..7732302 100644
--- a/llvm/lib/DebugInfo/PDB/PDBContext.cpp
+++ b/llvm/lib/DebugInfo/PDB/PDBContext.cpp
@@ -19,6 +19,7 @@
 
 using namespace llvm;
 using namespace llvm::object;
+using namespace llvm::pdb;
 
 PDBContext::PDBContext(const COFFObjectFile &Object,
                        std::unique_ptr<IPDBSession> PDBSession)