rm old wikibugs - replaced by pywikibugs

i don't see this being used anymore

wikibugs on freenode is now on labs

wikibugs [~pywikibug@wikimedia/bot/pywikibugs]
ircname  : Wikibugs v2.0, https://tools.wmflabs.org/wikibugs/

and if this is gone then the only remaining
bot that uses ircecho is icinga-wm (role echoirc)

we once had 4 bots using ircecho and we already deleted
the gerrit (grrrit-wm) and the openstack one (formerly labs-storage-wm)

Change-Id: I6817cd1e1c9b04b41c6e11e7124ce93506df4246