cmGeneratedFileStream: clang-tidy applied to remove redundant ``c_str`` calls

After changing the ``cmGeneratedFileStream`` methods to accept
``std::string const&`` instead of ``const char*`` we don't
need to call ``std::string::c_str`` anymore when passing
a ``std::string`` to a ``cmGeneratedFileStream`` method.

This patch removes all redundant ``std::string::c_str``
calls when passing a string to a ``cmGeneratedFileStream`` method.

It was generated by building CMake with clang-tidy enabled using
the following options:

-DCMAKE_CXX_CLANG_TIDY=/usr/bin/clang-tidy-4.0;-checks=-*,readability-redundant-string-cstr;-fix;-fix-errors

1 files changed, 1 insertions, 1 deletions

diff --git a/Source/cmCacheManager.cxx b/Source/cmCacheManager.cxx
index c6a1cff..5091c97 100644
--- a/Source/cmCacheManager.cxx
+++ b/Source/cmCacheManager.cxx
@@ -234,7 +234,7 @@ bool cmCacheManager::SaveCache(const std::string& path, cmMessenger* messenger)
 {
   std::string cacheFile = path;
   cacheFile += "/CMakeCache.txt";
-  cmGeneratedFileStream fout(cacheFile.c_str());
+  cmGeneratedFileStream fout(cacheFile);
   fout.SetCopyIfDifferent(true);
   if (!fout) {
     cmSystemTools::Error("Unable to open cache file for save. ",