coccinelle: make use of SYNTHETIC_ERRNO

Ideally, coccinelle would strip unnecessary braces too. But I do not see any
option in coccinelle for this, so instead, I edited the patch text using
search&replace to remove the braces. Unfortunately this is not fully automatic,
in particular it didn't deal well with if-else-if-else blocks and ifdefs, so
there is an increased likelikehood be some bugs in such spots.

I also removed part of the patch that coccinelle generated for udev, where we
returns -1 for failure. This should be fixed independently.

src/notify/notify.c

@@ -96,10 +96,9 @@ static int parse_argv(int argc, char *argv[]) {
                 case ARG_PID:
 
                         if (optarg) {
-                                if (parse_pid(optarg, &arg_pid) < 0) {
-                                        log_error("Failed to parse PID %s.", optarg);
-                                        return -EINVAL;
-                                }
+                                if (parse_pid(optarg, &arg_pid) < 0)
+                                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                               "Failed to parse PID %s.", optarg);
                         } else
                                 arg_pid = getppid();
 
@@ -208,10 +207,9 @@ static int run(int argc, char* argv[]) {
         r = sd_pid_notify(arg_pid ? arg_pid : getppid(), false, n);
         if (r < 0)
                 return log_error_errno(r, "Failed to notify init system: %m");
-        if (r == 0) {
-                log_error("No status data could be sent: $NOTIFY_SOCKET was not set");
-                return -EOPNOTSUPP;
-        }
+        if (r == 0)
+                return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                       "No status data could be sent: $NOTIFY_SOCKET was not set");
         return 0;
 }