Fix minor PSR2 incompatibilities throughout the source

The update to the scrutinizer build-script and the switch to the "official" phpcs PSR2 standard revealed some errors: https://scrutinizer-ci.com/g/bzikarsky/gelf-php/inspections/1fa5fbe7-acd6-43a3-b302-c2a39ba2afdb/issues/

Those need to be fixed