oxdisco: change permission checking from "login" to "metadata"

Outlook seems to perform Autodiscover requests not only for the
anchor mailbox, but also for shared stores. That's a bit weird, but
oh well. As Autodiscover is "just metadata" anyway, the strict
permission check to be able to login is too much.

References: DESK-1466

doc/changelog.rst

@@ -1,3 +1,11 @@
+Development 2.19.1
+==================
+
+Fixes:
+
+* oxdisco: allow autodiscover for room/equipment stores
+
+
 Gromox 2.19 (2023-12-04)
 ========================
 

exch/oxdisco.cpp

@@ -349,7 +349,7 @@ http_status OxdiscoPlugin::proc(int ctx_id, const void *content, uint64_t len) t
 
 	sql_meta_result mres{};
 	if (strncasecmp(email, public_folder_email, 19) != 0) {
-		auto err = mysql.meta(email, 0, mres);
+		auto err = mysql.meta(email, WANTPRIV_METAONLY, mres);
 		if (err != 0) {
 			mlog(LV_DEBUG, "oxdisco: unknown mailbox \"%s\": %s", email, strerror(err));
 			return die(ctx_id, 404, "Not Found");