pidgin/pidgin

Remove the oscar protocol plugin from po/POTFILES.in
release-2.x.y v2.14.3
2021-04-08, Gary Kramlich
723c284ecfa1
Remove the oscar protocol plugin from po/POTFILES.in

Testing Done:
Ran `make dist` successfully.

Reviewed at https://reviews.imfreedom.org/r/601/
installed_m4=purple.m4
EXTRA_DIST=$(installed_m4)
m4datadir=$(datadir)/aclocal
m4data_DATA=$(installed_m4)