Shorten the blob returned by .id() a bit.

src/vmod_file.c

@@ -699,7 +699,7 @@ VCL_BLOB
 vmod_reader_id(VRT_CTX, struct VPFX(file_reader) *rdr)
 {
 	time_t secs;
-	long nsecs;
+	uint32_t nsecs;
 	dev_t dev;
 	ino_t ino;
 	uintptr_t snap;
@@ -714,7 +714,7 @@ vmod_reader_id(VRT_CTX, struct VPFX(file_reader) *rdr)
 	AZ(pthread_rwlock_rdlock(&rdr->lock));
 	ERRCHK(ctx, rdr, "id", NULL);
 	secs = rdr->info->mtime.tv_sec;
-	nsecs = rdr->info->mtime.tv_nsec;
+	nsecs = (uint32_t) rdr->info->mtime.tv_nsec;
 	dev = rdr->info->dev;
 	ino = rdr->info->ino;
 	AZ(pthread_rwlock_unlock(&rdr->lock));