timesyncd,resolved,machinectl: drop calls to sd_event_get_exit_code()

In all three cases, sd_event_loop() will return the exit code anyway.
If sd_event_loop() returns negative, failure is logged and results in an
immediate return. Otherwise, we don't care if sd_event_loop() returns 0
or positive, because the return value feeds into DEFINE_MAIN_FUNCTION(), which
doesn't make the distinction.

src/machine/machinectl.c

@@ -1309,7 +1309,7 @@ static int on_machine_removed(sd_bus_message *m, void *userdata, sd_bus_error *r
 static int process_forward(sd_event *event, PTYForward **forward, int master, PTYForwardFlags flags, const char *name) {
         char last_char = 0;
         bool machine_died;
-        int ret = 0, r;
+        int r;
 
         assert(event);
         assert(master >= 0);
@@ -1355,8 +1355,7 @@ static int process_forward(sd_event *event, PTYForward **forward, int master, PT
                         log_info("Connection to machine %s terminated.", name);
         }
 
-        sd_event_get_exit_code(event, &ret);
-        return ret;
+        return 0;
 }
 
 static int parse_machine_uid(const char *spec, const char **machine, char **uid) {

src/resolve/resolved.c

@@ -81,9 +81,7 @@ static int run(int argc, char *argv[]) {
         if (r < 0)
                 return log_error_errno(r, "Event loop failed: %m");
 
-        (void) sd_event_get_exit_code(m->event, &r);
-
-        return r;
+        return 0;
 }
 
 DEFINE_MAIN_FUNCTION(run);

src/timesync/timesyncd.c

@@ -169,9 +169,7 @@ static int run(int argc, char *argv[]) {
                         log_debug_errno(r, "Failed to touch %s, ignoring: %m", CLOCK_FILE);
         }
 
-        (void) sd_event_get_exit_code(m->event, &r);
-
-        return r;
+        return 0;
 }
 
 DEFINE_MAIN_FUNCTION(run);