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/cmCTest.cxx b/Source/cmCTest.cxx
index 95edd8b..3d3d526 100644
--- a/Source/cmCTest.cxx
+++ b/Source/cmCTest.cxx
@@ -818,7 +818,7 @@ bool cmCTest::OpenOutputFile(const std::string& path, const std::string& name,
     }
   }
   std::string filename = testingDir + "/" + name;
-  stream.Open(filename.c_str());
+  stream.Open(filename);
   if (!stream) {
     cmCTestLog(this, ERROR_MESSAGE,
                "Problem opening file: " << filename << std::endl);