Add support for OmniOS

Under OmniOS, /home is an autofs mount point by default; /export/home is the default parent directory of local home directories.

This may also be valid for other Illumos derivatives and Solaris; I didn't have anything other than OmniOS available to test on.  (I'm not sure if /bin/bash is available as a shell universally; the /export/home behavior is universal on Solaris-derivatives AFAIK.)

Thanks for considering this pull request.