pidgin/pidgin

Replace the subproject build with a debian build and add fedora and clang builds

Testing Done:
Ran the convey plans

Reviewed at https://reviews.imfreedom.org/r/746/
REVIEWBOARD_URL = "https://reviews.imfreedom.org/"
REPOSITORY = "pidgin/pidgin"
REPOSITORY_TYPE = "mercurial"
BRANCH = "default"
LAND_DEST_BRANCH = "default"
LAND_PUSH = False