Qualify dwarf namespace inside llvm namespace.

llvm-svn: 26409
diff --git a/llvm/lib/CodeGen/DwarfWriter.cpp b/llvm/lib/CodeGen/DwarfWriter.cpp
index 3f28832..d08e777 100644
--- a/llvm/lib/CodeGen/DwarfWriter.cpp
+++ b/llvm/lib/CodeGen/DwarfWriter.cpp
@@ -26,7 +26,7 @@
 #include <iostream>
 
 using namespace llvm;
-using namespace dwarf;
+using namespace llvm::dwarf;
 
 static cl::opt<bool>
 DwarfVerbose("dwarf-verbose", cl::Hidden,