irc: fix memory leak when updating modes of channel

ChangeLog

@@ -62,6 +62,7 @@ Version 0.4.0 (under dev!)
   aspell.check.suggestions (task #12061)
 * aspell: fix creation of spellers when number of dictionaries is different
   between two buffers
+* irc: fix memory leak when updating modes of channel
 * irc: add tags "irc_nick1_xxx" and "irc_nick2_yyy" in message displayed for
   command "NICK"
 * irc: return git version in CTCP VERSION and FINGER by default, add "$git"

src/plugins/irc/irc-mode.c

@@ -241,7 +241,7 @@ irc_mode_channel_update (struct t_irc_server *server,
                 snprintf (str_temp, length, "%s %s", new_modes, new_args);
                 if (channel->modes)
                     free (channel->modes);
-                channel->modes = strdup (str_temp);
+                channel->modes = str_temp;
             }
         }
         else
@@ -250,11 +250,12 @@ irc_mode_channel_update (struct t_irc_server *server,
                 free (channel->modes);
             channel->modes = strdup (new_modes);
         }
-
-        free (new_modes);
-        free (new_args);
     }
 
+    if (new_modes)
+        free (new_modes);
+    if (new_args)
+        free (new_args);
     if (str_modes)
         free (str_modes);
     if (argv)