Fix a case when plugin doesnt restart

This occurred when no channels are available to join when rejoin_on_kick config
option is set to false.
Adjust irc test for cleaning up on kick

An irc output should cleanup after being kicked if it has no channels left
to join.
Merge pull request #1002 from ecnahc515/fix_irc_restart_norejoin_kick

Fix a case when plugin doesnt restart