Eliminate an unnecessary .c_str()

llvm-svn: 194228
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index c1999e8..98745ac 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1791,7 +1791,7 @@
     llvm::sys::path::append(systemVersionFile, "Library");
     llvm::sys::path::append(systemVersionFile, "CoreServices");
     llvm::sys::path::append(systemVersionFile, "SystemVersion.plist");
-    if (!llvm::MemoryBuffer::getFile(systemVersionFile.c_str(), buffer)) {
+    if (!llvm::MemoryBuffer::getFile(systemVersionFile.str(), buffer)) {
       code = hash_combine(code, buffer.get()->getBuffer());
 
       struct stat statBuf;