Do not enable owncloud apache config by default

[deflomu]

When installing owncloud as a debian package or when updating owncloud via apt the packaged owncloud apache config is enabled by default.

I have disabled the default config because I have an extra site for owncloud. I can imagine there are more cases where the default config with the default alias /ownlcoud is not desired.

I think the config should be installed in /etc/apache/conf-available but not be enabled by default. The user could be notified by the post installation script that the config can be enabled with a2enconf owncloud.conf

See https://github.com/owncloud/administration/blob/master/jenkins/obs_integration/templates/owncloud/8.2/debian.PACKNAME-deps-php5.postinst#L38