Fix detection of exception phase for Beta/GA

The special case of Beta->GA was not properly checking for whether the Beta release was listed second in the set of active releases from Product Pages.

Additionally, indentation on the "in_exception_phase" assignment was incorrect, causing it to always be based on the last-seen entry in the list of active releases.

Resolves: https://issues.redhat.com/browse/CS-2517

Signed-off-by: Stephen Gallagher sgallagh@redhat.com