Inject config into checkserver and cleanup tests

Conflicts:
	lib/private/util.php
Don't complain about non-writable datadirs before we're installed

Conflicts:
	lib/private/util.php
Check for writable datadir during setup
Don't test for htaccess if we cant write into the datadir anyway
Try to create datadirectory to test whether the .htaccess works

Fixes https://github.com/owncloud/core/pull/11299#issuecomment-56968588 and also https://github.com/owncloud/core/issues/10628 together with https://github.com/owncloud/core/pull/11299#issuecomment-56968588 when backported.
Merge pull request #11299 from owncloud/barkport-10934

[stable7] Don't complain about non-writable datadirs before we're installed