Use LOG instead of LOG_DEVEL

According to https://github.com/neutrinolabs/xrdp/wiki/Logging,
it may be better to emit this log message because this log is
useful for system administrator to know whether RestrictOutboundClipboard
configuration works or not

And raise log level to info because it is informative for system
administrator.

sesman/chansrv/clipboard.c

@@ -2533,7 +2533,7 @@ clipboard_xevent(void *xevent)
             }
             else
             {
-                LOG_DEVEL(LOG_LEVEL_DEBUG, "outbound clipboard is restricted because of config");
+                LOG(LOG_LEVEL_INFO, "outbound clipboard is restricted because of config");
                 return 1;
             }
             break;