Fix superfluous traling semicolon in cached config

[bcremer]

The trailing semicolon gets already yielded by VarExporter::export.

Q	A
Bugfix	yes(ish)

The generated cache file contained an extra semicolon:

<?php
return [
    'service_manager' => [
    ]
];
;

This is more of an cosmetic fix as the traling semicolon should not have any negativ impact.