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/shared/serialize.c

@@ -153,10 +153,10 @@ int deserialize_dual_timestamp(const char *value, dual_timestamp *t) {
                 return -EINVAL;
 
         r = sscanf(value, "%" PRIu64 "%" PRIu64 "%n", &a, &b, &pos);
-        if (r != 2) {
-                log_debug("Failed to parse dual timestamp value \"%s\".", value);
-                return -EINVAL;
-        }
+        if (r != 2)
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "Failed to parse dual timestamp value \"%s\".",
+                                       value);
 
         if (value[pos] != '\0')
                 /* trailing garbage */