statefiles: don't consider no hostname as broken

Commit e568bde changed the OAF_BROKEN_HOSTNAME flag to a boolean, but at
the same time changed the semantics slightly so that no hostname was
also considered broken (rather, no hostname means it's neither valid nor
invalid).

So, add a simple fix for this.

Closes: openwrt#350

(cherry picked from commit 6b88c31)
Signed-off-by: David Härdeman <david@hardeman.nu>
Link: openwrt#351
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

Author: Alphix

src/statefiles.c

@@ -488,7 +488,7 @@ static void statefiles_write_state6(struct write_ctxt *ctxt, struct dhcpv6_lease
 		fprintf(ctxt->fp,
 			"# %s %s %x %s%s %" PRId64 " %" PRIx64 " %" PRIu8,
 			ctxt->iface->ifname, duidbuf, ntohl(lease->iaid),
-			lease->hostname_valid ? "" : "broken\\x20",
+			lease->hostname && !lease->hostname_valid ? "broken\\x20": "",
 			lease->hostname ? lease->hostname : "-",
 			(lease->valid_until > ctxt->now ?
 			 (int64_t)(lease->valid_until - ctxt->now + ctxt->wall_time) :
@@ -524,7 +524,7 @@ static void statefiles_write_state4(struct write_ctxt *ctxt, struct dhcpv4_lease
 		"# %s %s ipv4 %s%s %" PRId64 " %x 32 %s/32\n",
 		ctxt->iface->ifname,
 		ether_ntoa((struct ether_addr *)lease->hwaddr),
-		lease->hostname_valid ? "" : "broken\\x20",
+		lease->hostname && !lease->hostname_valid ? "broken\\x20" : "",
 		lease->hostname ? lease->hostname : "-",
 		(lease->valid_until > ctxt->now ?
 		 (int64_t)(lease->valid_until - ctxt->now + ctxt->wall_time) :