Remove more superfluous .str() and replace std::string concatenation with Twine.

Following r233392, http://llvm.org/viewvc/llvm-project?rev=233392&view=rev.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233555 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/CommandLine.cpp

@@ -313,7 +313,7 @@ static Option *LookupNearestOption(StringRef Arg,
         if (RHS.empty() || !PermitValue)
           NearestString = OptionNames[i];
         else
-          NearestString = std::string(OptionNames[i]) + "=" + RHS.str();
+          NearestString = (Twine(OptionNames[i]) + "=" + RHS).str();
       }
     }
   }