isisd: fold up isis_circuit_is_type_set()

see previous commit.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/isisd/isis_events.c b/isisd/isis_events.c
index ebd86a5..abc4471 100644
--- a/isisd/isis_events.c
+++ b/isisd/isis_events.c
@@ -147,7 +147,7 @@
 }
 
 void
-isis_event_circuit_type_change (struct isis_circuit *circuit, int newtype)
+isis_circuit_is_type_set (struct isis_circuit *circuit, int newtype)
 {
   if (circuit->state != C_STATE_UP)
   {