Bug 33687

If there is some fatal error during parsing of
configuration file (for example when file is empty
or there is name mismatch between file name and
name in data) it is not possible to create valid
instance of configuration data class -> parser
should probably log it (it is already done) and
return null. null return value must be correctly
handled by caller (its parent like WindowManager
-> Mode). This behaviour is also covered by unit
tests.