Added mount.active functionality for Solaris.

Without this change, 2014.1.3 on Solaris 10 reports
```
$ sudo salt 'sandbox-solaris*' mount.active
sandbox-solaris.example.com:
    The minion function caused an exception: Traceback (most recent call last):
      File "/opt/csw/lib/python2.6/site-packages/salt/minion.py", line 793, in _thread_return
        return_data = func(*args, **kwargs)
      File "/opt/csw/lib/python2.6/site-packages/salt/modules/mount.py", line 94, in active
        _active_mountinfo(ret)
      File "/opt/csw/lib/python2.6/site-packages/salt/modules/mount.py", line 30, in _active_mountinfo
        _list = _list_mounts()
      File "/opt/csw/lib/python2.6/site-packages/salt/modules/mount.py", line 25, in _list_mounts
        ret[comps[2]] = comps[0]
    IndexError: list index out of range
```