pidgin/pidgin

Remove PurpleProtocol->login and ->close as they're no longer necessary

These were left around for the old protocols and the replacement code used them
as a fallback.

Testing Done:
Ran with the turtles.

Reviewed at https://reviews.imfreedom.org/r/3081/
REVIEWBOARD_URL = "https://reviews.imfreedom.org/"
REPOSITORY = "pidgin/pidgin"
REPOSITORY_TYPE = "mercurial"
BRANCH = "default"
LAND_DEST_BRANCH = "default"
LAND_PUSH = False