FIX: Unit test file - fixed declaration of the connection.

src/connection_m.fun

@@ -15,7 +15,7 @@ type(neuron_t), pointer :: n2_p
 
 type(neuron_t), pointer :: dummy_p
 
-type(interval_connection_t), pointer :: con
+type(connection_t), pointer :: con
 
 !------------------------!---------------------------------------------------------------
 ! Setup before each test !