tipc: Eliminate useless initialization when creating subscriber

Removes initialization of a local variable that is always assigned
a different value before it is referenced.

Signed-off-by: Allan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>