dns_easydns: match the TXT record by its rdata when removing (#7199)

dns_easydns_rm() picked the first id in the search response and ignored
$txtvalue. When two challenge records exist under the same host - for
example when example.com and *.example.com are issued as separate
certificates - a concurrent run's record could be deleted instead of
our own.

Select the record by its rdata instead, following the dns_cf.sh
convention of matching name + value. tr '{' '\n' puts one record per
line, so both _egrep_o branches - egrep -o and the BRE sed fallback -
return the same single id. Without it the sed fallback would return
only the last match, since .* is greedy.

An empty record_id is now treated as "nothing to remove" and returns 0,
rather than being reported as an error.

Also add the credential check that _rm was missing. It deliberately
does not call _saveaccountconf_mutable, as _add already does that.

Co-authored-by: wurzelpanzer <wurzelpanzer@maximolider.net>

dnsapi/dns_easydns.sh

@@ -75,6 +75,11 @@ dns_easydns_rm() {
   EASYDNS_Token="${EASYDNS_Token:-$(_readaccountconf_mutable EASYDNS_Token)}"
   EASYDNS_Key="${EASYDNS_Key:-$(_readaccountconf_mutable EASYDNS_Key)}"
 
+  if [ -z "$EASYDNS_Token" ] || [ -z "$EASYDNS_Key" ]; then
+    _err "You didn't specify an easydns.net token or api key. Signup at https://cp.easydns.com/manage/security/api/signup.php"
+    return 1
+  fi
+
   _debug "First detect the root zone"
   if ! _get_root "$fulldomain"; then
     _err "invalid domain"
@@ -91,23 +96,20 @@ dns_easydns_rm() {
     return 1
   fi
 
-  count=$(printf "%s\n" "$response" | _egrep_o "\"count\":[^,]*" | cut -d : -f 2)
-  _debug count "$count"
-  if [ "$count" = "0" ]; then
-    _info "Don't need to remove."
-  else
-    record_id=$(printf "%s\n" "$response" | _egrep_o "\"id\":\"[^\"]*\"" | cut -d : -f 2 | tr -d \" | head -n 1)
+  record_id=$(printf "%s\n" "$response" | tr '{' '\n' | grep "\"rdata\":\"$txtvalue\"" | _egrep_o "\"id\":\"[^\"]*\"" | cut -d : -f 2 | tr -d \")
   _debug "record_id" "$record_id"
+
   if [ -z "$record_id" ]; then
-      _err "Can not get record id to remove."
-      return 1
+    _info "Don't need to remove."
+    return 0
   fi
+
   if ! _EASYDNS_rest DELETE "zones/records/$_domain/$record_id"; then
     _err "Delete record error."
     return 1
   fi
+
   _contains "$response" "\"status\":200"
-  fi
 
 }