Fix reported coding standards problems

While our test suite still passes with flying colors, it now reports 20 coding standard issues for this module. And it seems it will now set patches back to "Needs work" for them (if they occur in a file that was changed by the patch – but even if the problem was there before), so fixing this is now a bit more urgent.

#2839932: PluginNotFoundException exception in Views when using an index with multiple entity types, where we discovered this problem, will already fix four of the issues – let's fix the other 16 here.