test: correct enum misassignment

CC     src/test/test_job_type-test-job-type.o
../src/test/test-job-type.c:40:25: warning: implicit conversion from enumeration type
      'enum UnitType' to different enumeration type 'ServiceType' (aka 'enum ServiceType')
      [-Wconversion]
                .type = UNIT_SERVICE
                        ^~~~~~~~~~~~

src/test/test-job-type.c

@@ -37,7 +37,7 @@ int main(int argc, char*argv[]) {
         /* fake a unit */
         static Service s = {
                 .meta.load_state = UNIT_LOADED,
-                .type = UNIT_SERVICE
+                .type = SERVICE_SIMPLE,
         };
         Unit *u = UNIT(&s);