remove SAFEMODE

I have no real solution in mind, I'll just keep a running list of what SAFEMODE does here, since I have been bitten in the backparts by it multiple times and the documentation really doesn't cut it (“Don’t use fancy stuff (EDNS, 0x20, …)”).

• turns off Ox20 randomization
• turns off server selection (to be changed in !1030 (merged))
• turns off some EDNS stuff that I don't understand
• ensures that there is a retry after REFUSED (see code below; this means that if you overwrite query->SAFEMODE after this, the resolver may cycle on REFUSED)

static int resolve_badmsg(knot_pkt_t *pkt, struct kr_request *req, struct kr_query *query)
{

#ifndef STRICT_MODE
	/* Work around broken auths/load balancers */
	if (query->flags.SAFEMODE) {
		return resolve_error(pkt, req);
	} else if (query->flags.NO_MINIMIZE) {
		query->flags.SAFEMODE = true;
		return KR_STATE_DONE;
	} else {
		query->flags.NO_MINIMIZE = true;
		return KR_STATE_DONE;
	}
#else
		return resolve_error(pkt, req);
#endif
}

Removing it, is probably a better idea: especially with the new server selection error reporting we could probably make the workarounds more granular than they are now.