Fix version comparison with minor and patch level requirements

If an app requires a specific minor or path level server version,
the version_compare prevented the installation as only the major
version had been compared and that checks obviously returns `false`.

Now the full version is used for comparison, making it possible to
release apps for a specific minor or patch level version of Nextcloud.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>