pidgin/pidgin

Remove Finch logging preferences but add Credential Provider preference.

The logging preferences were removed because they were removed when the History API was merged, but their Finch UI remained. Also there's currently no preference for the history adapter so no reason to put it in now.

Testing Done:
Opened the preference window in finch and made sure the settings saved.

Reviewed at https://reviews.imfreedom.org/r/1595/
REVIEWBOARD_URL = "https://reviews.imfreedom.org/"
REPOSITORY = "pidgin/pidgin"
REPOSITORY_TYPE = "mercurial"
BRANCH = "default"
LAND_DEST_BRANCH = "default"
LAND_PUSH = False