It's better to encode the string to prevent possible (yet unknown) bugs in combination with PHP's type juggling.

Previously the boolean statements evaluated to either an empty string (false) or a not empty one (true, then it was 1). Not it always evaluates to false or true.

This also removes a stray - that was not intended there but shouldn't have produced any bugs. Just to increase readability.

Thanks @nickvergessen for spotting.

Addresses https://github.com/owncloud/core/pull/13235/files#r22852319