Remove flickrApiUrl from $wgUploadWizardConfig

The current value was breaking if browsing the site from http
(It always needs to be https per flickr policy). This was fixed
in the extension. Since value should be the same, simply stop
overriding the UploadWizard extension.

Also remove comment which was beside the line, but seems unrelated.

Bug: 67298
Change-Id: I91960a444491dee91691f8697371c293ed7838a5