Fix: If ticket/1 is inaccessible, roust would throw in authenticated

[erdgeist]

The function authenticated? in roust.rb would check for an Unauthenticated exception thrown from the function show('1').

However, if an http request to ticket/1 returns a # You are not allowed to display ticket 1., ticket_show('1') would continue to call parse_ticket_attributes which happily tries to expand the response body, creates a hash = body_to_hash(body) assuming that an id = ticket/1 field is present in the response body.

Once it tries to access its 'id' key in hash['id'] = hash['id'].split('/').last, it throws undefined method split' for nil:NilClass`.

Additionally, if the ticket/1 is not present at all, authenticated? would untruthfully not return true, because the if show('1') test fails.

This patch prevents ticket_show() to continue if the ticket is disallowed and properly returns true in authenticate?, if no exception is thrown.

[erdgeist]

Ping.