Fixing build error introduced with r332759.

llvm-svn: 332762
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index 11cec59..9bdcfcb 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -170,7 +170,7 @@
   }
   llvm::DWARFDebugRnglistTable Table;
   if (Error E = Table.extractHeaderAndOffsets(DA, &Offset))
-    return E;
+    return std::move(E);
   return Table;
 }