Move pdb code into pdb namespace.

llvm-svn: 268544
diff --git a/llvm/tools/llvm-pdbdump/VariableDumper.h b/llvm/tools/llvm-pdbdump/VariableDumper.h
index 7d4af8a..4f00358 100644
--- a/llvm/tools/llvm-pdbdump/VariableDumper.h
+++ b/llvm/tools/llvm-pdbdump/VariableDumper.h
@@ -15,6 +15,9 @@
 namespace llvm {
 
 class StringRef;
+
+namespace pdb {
+
 class LinePrinter;
 
 class VariableDumper : public PDBSymDumper {
@@ -37,5 +40,5 @@
   LinePrinter &Printer;
 };
 }
-
+}
 #endif