pidgin/purple-plugin-pack

Remove plugin_pack.spec.in as we haven't provided rpms in a long time

Testing Done:
Ran `ninja dist` and verified no issues.

Reviewed at https://reviews.imfreedom.org/r/2404/
# SSL Info
dependencies: libpurple
authors: Gary Kramlich
introduced: 1.0beta1
Displays info about your currently loaded SSL plugin.