Updated some code in zenmap/zenmapGUI/DiffCompare.py and zenmap/zenmapGUI/ScanNmapOutputPage.py to work properly with the code from r32983
Modifying r32985 based on Henri Doreau's comment

"For sequences, (strings, lists, tuples), use the fact that empty
sequences are false." PEP-0008 says[1].

[1] http://legacy.python.org/dev/peps/pep-0008/