tipc: fix memory leak of publications

Commit 1bb8dce5 ("tipc: fix memory
leak during module removal") introduced a memory leak issue: when
name table is stopped, it's forgotten that publication instances are
freed properly. Additionally the useless "continue" statement in
tipc_nametbl_stop() is removed as well.

Reported-by: Jason <huzhijiang@gmail.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>