Update unit tests (ARMmbed#59)

Remove unnecessary stub eventOS_event_send

Author: Arto Kinnunen

test/coap-service/unittest/stub/eventOS_event_stub.c

@@ -9,11 +9,6 @@
 
 eventOs_event_stub_def eventOs_event_stub;
 
-int8_t eventOS_event_send(arm_event_s *event)
-{
-    return eventOs_event_stub.int8_value;
-}
-
 int8_t eventOS_event_handler_create(void (*handler_func_ptr)(arm_event_s *), uint8_t init_event_type)
 {
     eventOs_event_stub.event_ptr = handler_func_ptr;