Fix -Wpessimizing-move by removing call to std::move

llvm-svn: 236281
diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index 340a659..38848b0 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -969,7 +969,7 @@
     llvm::sys::fs::make_absolute(Path);
 
     auto I = Entry.second;
-    FilenameStrs[I] = std::move(std::string(Path.begin(), Path.end()));
+    FilenameStrs[I] = std::string(Path.begin(), Path.end());
     FilenameRefs[I] = FilenameStrs[I];
   }