router: Remove racy gocheck assertion from goroutine
router: Remove racy gocheck assertion from goroutine

Signed-off-by: Jonathan Rudenberg <3692bfa45759a67d83aedf0045f6cb635a966abf@titanous.com>

flynn/flynn,flynn/flynn,lmars/flynn,lmars/flynn,flynn/flynn,philiplb/flynn,philiplb/flynn,flynn/flynn,lmars/flynn,flynn/flynn,philiplb/flynn,lmars/flynn,lmars/flynn,philiplb/flynn,philiplb/flynn