Fix Clang-tidy readability-redundant-string-cstr warnings

Reviewers: aaron.ballman, mehdi_amini, dblaikie

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D26206

llvm-svn: 285799
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index ff22ed8..86a3c87 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1469,7 +1469,7 @@
       Path = Buffer.str();
     }
 
-    Opts.AddPath(Path.c_str(), Group, IsFramework,
+    Opts.AddPath(Path, Group, IsFramework,
                  /*IgnoreSysroot*/ true);
     IsIndexHeaderMap = false;
   }