coloredstderr.c: Use #include <config.h>.

This ensures that config.h from the build directory is preferred over a
possible file of the same name in the source directory.

src/coloredstderr.c

@@ -18,7 +18,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "config.h"
+#include <config.h>
 
 /* Must be loaded before the following headers. */
 #include "ldpreload.h"