Revert "DebugInfo: Include .dwo file name when hashing multiple CUs in a single file"

This reverts commit r304119 and r304118. GreenDragon is broken.

llvm-svn: 304125
diff --git a/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp b/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
index 201030f..ff04ec7 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
@@ -380,12 +380,10 @@
 /// DWARF4 standard. It is an md5 hash of the flattened description of the DIE
 /// with the inclusion of the full CU and all top level CU entities.
 // TODO: Initialize the type chain at 0 instead of 1 for CU signatures.
-uint64_t DIEHash::computeCUSignature(StringRef DWOName, const DIE &Die) {
+uint64_t DIEHash::computeCUSignature(const DIE &Die) {
   Numbering.clear();
   Numbering[&Die] = 1;
 
-  if (!DWOName.empty())
-    Hash.update(DWOName);
   // Hash the DIE.
   computeHash(Die);