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/cmExportCommand.cxx b/Source/cmExportCommand.cxx
index 4e1d771..7d5c4f8 100644
--- a/Source/cmExportCommand.cxx
+++ b/Source/cmExportCommand.cxx
@@ -339,7 +339,7 @@ void cmExportCommand::StorePackageRegistryDir(std::string const& package,
   fname += "/";
   fname += hash;
   if (!cmSystemTools::FileExists(fname)) {
-    cmGeneratedFileStream entry(fname.c_str(), true);
+    cmGeneratedFileStream entry(fname, true);
     if (entry) {
       entry << content << "\n";
     } else {