Move pdb code into pdb namespace.

llvm-svn: 268544
diff --git a/llvm/lib/DebugInfo/PDB/PDBSymbolPublicSymbol.cpp b/llvm/lib/DebugInfo/PDB/PDBSymbolPublicSymbol.cpp
index bd6fe89..97d6687 100644
--- a/llvm/lib/DebugInfo/PDB/PDBSymbolPublicSymbol.cpp
+++ b/llvm/lib/DebugInfo/PDB/PDBSymbolPublicSymbol.cpp
@@ -15,6 +15,7 @@
 #include <utility>
 
 using namespace llvm;
+using namespace llvm::pdb;
 
 PDBSymbolPublicSymbol::PDBSymbolPublicSymbol(
     const IPDBSession &PDBSession, std::unique_ptr<IPDBRawSymbol> Symbol)