Small fix to prevent an exception from being thrown on bad input.
Small fix to prevent an exception from being thrown on bad input.

* tools/hook-scripts/mailer/mailer.py:
  - wrap a conversion to an integer with a try/except. if the argument is
    not an integer, then they goofed -- display the usage.

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