pidgin/pidgin

Set the prereq type for all Protocol interfaces to PurpleProtocol

Testing Done:
Compiled and ran without an obvious issues.

Reviewed at https://reviews.imfreedom.org/r/888/
[main]
host = https://www.transifex.com
[pidgin.pidgin_pot-for-development-branch]
file_filter = po/<lang>.po
source_file = po/pidgin.pot
source_lang = en