Code review comment for lp:~meths/openlp/trivialfixes

Okay I've fudged a comparison by forcing the plugin to try and load powerpoint and powerpoint viewer when neither are installed. Top section is the information given in a log exception, bottom line is information from the log error:

2009-09-18 12:43:14,010 PresentationPlugin ERROR Failed to setup plugin for Powerpoint
Traceback (most recent call last):
  File "D:\Projects\OpenLP\openlp\trunk\openlp\plugins\presentations\presentationplugin.py", line 97, in check_pre_conditions
    powerpoint = PowerpointController()
NameError: global name 'PowerpointController' is not defined

2009-09-18 12:43:14,010 PresentationPlugin ERROR Reason : (<type 'exceptions.NameError'>, NameError("global name 'PowerpointController' is not defined",), <traceback object at 0x0387A670>)