Flickr plugin adds JavaScript to every admin page

[michaeltwofish]

After [1322] the Flickr media silo adds the 'flickr' media type to the habari JavaScript object on every page in admin. The attached patch adds selectively only to the publish page.

Note, if the rumoured Controller::get_handler()->admin_page property has been included in adminhandler, that should be used instead.

[michaeltwofish]

The patch caused an error on the admin dashboard (because it checked against Controller::get_handler->handler_varspage?, which doesn't exist on the dashboard). The patch has now been corrected.

[michaeltwofish]

The second patch uses the new action_admin_{method}_{page} hooks introduced in r1336 to determine whether to add the media type, and is therefore much more readable.

[dmondark]

The right component of this ticket is Plugins since its related to Flickr Silo core plugin.

[dmondark]

Tested flickrsilo_only_publish.2.patch and it works fine. The 'flickr' media type only exists in the publish pages.

[ringmaster]

In r1365.