Following up to r33335, replace 'print()' with 'print("")' to remove '()' output in gen-make.py --help. Also exit with error 1 on invalid argument.
Following up to r33335, replace 'print()' with 'print("")' to
remove '()' output in gen-make.py --help. Also exit with error 1 on
invalid argument.

* gen-make.py
  (_usage_exit): Make sure the printed tuple always contains a string
    and exit with error 1 instead of 0.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion