* Description
org-gnus-follow-link tries to select the Gnus frame if the user used
gnus-other-frame, the intention is to follow the previous action of the
user and now choose that Gnus frame too.
However it doesn't check if the frame is alive or not, resulting
in (wrong-type-argument frame-live-p #<frame>).

* Preconditions
- gnus-other-frame-object is a dead frame

* Steps to preproduce
1. Try to follow org-gnus link
2. Error

* Proposed change
Use the new org-link-frame-setup activate gnus-other-frame-object if
required.

The org-gnus-no-news function did not take care of if gnus should be
called directly of if should be called using the gnus-other-frame
function, i.e. when gnus-other-frame-object is set.
Take gnus-other-frame-object into account and call it if
gnus-other-frame-object is set or when the user chooses to do so
regardless. This ensures that gnus-other-frame-object always contains an
alive frame. The side effect is gnus-other-frame is used to ensure that
Gnus is called in the correct frame.

See attached patch.