Move pdb code into pdb namespace.

llvm-svn: 268544
diff --git a/llvm/lib/DebugInfo/PDB/PDBSymbolExe.cpp b/llvm/lib/DebugInfo/PDB/PDBSymbolExe.cpp
index c9e34ea..60101c1 100644
--- a/llvm/lib/DebugInfo/PDB/PDBSymbolExe.cpp
+++ b/llvm/lib/DebugInfo/PDB/PDBSymbolExe.cpp
@@ -14,6 +14,7 @@
 #include <utility>
 
 using namespace llvm;
+using namespace llvm::pdb;
 
 PDBSymbolExe::PDBSymbolExe(const IPDBSession &PDBSession,
                            std::unique_ptr<IPDBRawSymbol> Symbol)