[clang-query] Fix Clang-tidy readability-redundant-string-cstr warnings

[pcc]

LGTM

clang-query/tool/ClangQuery.cpp

if (Tool.buildASTs(ASTs) != 0)
     return 1;
 
   QuerySession QS(ASTs);
 
   if (!Commands.empty()) {
     for (cl::list<std::string>::iterator I = Commands.begin(),
                                          E = Commands.end();
          I != E; ++I) {
-      QueryRef Q = QueryParser::parse(I->c_str(), QS);
+      QueryRef Q = QueryParser::parse(*I, QS);
       if (!Q->run(llvm::outs(), QS))
         return 1;
     }
   } else if (!CommandFiles.empty()) {
     for (cl::list<std::string>::iterator I = CommandFiles.begin(),
                                          E = CommandFiles.end();
          I != E; ++I) {
       std::ifstream Input(I->c_str());
       if (!Input.is_open()) {
         llvm::errs() << argv[0] << ": cannot open " << *I << "\n";
         return 1;
       }
       while (Input.good()) {
         std::string Line;
         std::getline(Input, Line);
 
-        QueryRef Q = QueryParser::parse(Line.c_str(), QS);
+        QueryRef Q = QueryParser::parse(Line, QS);
         if (!Q->run(llvm::outs(), QS))
           return 1;
       }
     }
   } else {
     LineEditor LE("clang-query");
     LE.setListCompleter([&QS](StringRef Line, size_t Pos) {
       return QueryParser::complete(Line, Pos, QS);