Bug 17445: Move the params check after the authentication check

Bug 17445: Move the params check after the authentication check

If the user is not authorised to call this route, we would prefer to
raise a 403 instead of 400

Note that we wanted to submit tests for this change but the city code
does not let use do that (we are allowed to list/show cities even
without any permissions). The patrons.t is not complete enought and the
holds.t tests do not pass...

Tomas plans to submit tests but we reach the end of the hackfest ;)

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>