Add error message when some mandatory smb.conf options are not set

[cdelfosse]

The SAMBA plugin should check that the options "ldap user suffix", "ldap group suffix" and "ldap machine suffix" are set, instead of displaying this traceback:

Error while trying to load plugin samba
list index out of range
Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/mmc/agent.py", line 602, in loadPlugins
    if (func()):
  File "/usr/lib/python2.5/site-packages/mmc/plugins/samba/__init__.py", line 15                                          2, in activate
    if ldap.explode_rdn(smbconfsuffix)[0].lower() != ldap.explode_rdn(option[2])                                          [0].lower():
IndexError: list index out of range