[CRIU] Reworking dump_one_fd

[Cyrill Gorcunov]

Pavel, I guess this way it'll be more convenient to extend
dump_one_fd types assignement in future. In particular for
inotify I'll simply add

	...
+	else if (is_inotify(lfd))
+		p.type = FDINFO_INOTIFY;
	...