Clean up the test data in tearDownAfterClass()

The result of the listener should then be empty and can be removed
Remove testcleanuplistener.php
fix unit tests of mdb2scheamreader
Merge pull request #12342 from owncloud/fix-master-unit-tests

fix unit tests of mdb2scheamreader
[tx-robot] updated from transifex
Merge pull request #12328 from owncloud/remove-testcleanuplistener

Remove testcleanuplistener
migrated OC_Preferences::deleteAppFromAllUsers to deleteApp in \OCP\IConfig