fix error that mod is nil if unless matches in load_module_config

[timogoebel]

This does not work as intended in ruby. Please see this example:

ruby 2.1.3:

2.1.3 :001 > a = 'eins'
 => "eins"
2.1.3 :002 > b = 'zwo'
 => "zwo"
2.1.3 :003 >  c = a unless b
 => nil
2.1.3 :004 >

Even though you want c = b, c = nil.

Tested it with 1.8.7 as well. Same behavior.

[ripienaar]

thanks for fixing that