Don't point to file with .py ending that does not exist

     if utils.which(gubbins_exec) is None:

         # Check if the Gubbins C-program is available in its source directory (for tests/Travis)

         gubbins_bundled_exec = os.path.abspath(os.path.join(current_directory, '../src/gubbins'))

Index: gubbins/src/main.c

===================================================================

--- gubbins.orig/src/main.c

+++ gubbins/src/main.c

@@ -38,7 +38,7 @@ const char* program_name;

 void print_usage(FILE* stream, int exit_code)

 {

-  fprintf (stream, "This program is not supposed to be directly run. Use run_gubbins.py instead\n");

+  fprintf (stream, "This program is not supposed to be directly run. Use run_gubbins instead\n");

   fprintf (stream, "Usage:  %s [options] alignment_file\n", program_name);

   fprintf (stream, "Version: %s\n", PACKAGE_VERSION);

   fprintf (stream,