On, Special:NotifyTranslators, If "Which languages to notify:" is set to source language, it is throwing exception,

<code>
[715f2a93] /mw/index.php/%E0%AA%B5%E0%AA%BF%E0%AA%B6%E0%AB%87%E0%AA%B7:NotifyTranslators Exception from line 208 of /var/www/mw/extensions/TranslationNotifications/SpecialNotifyTranslators.php: A notification must not be sent only to translators to the source language.
Backtrace:
#0 [internal function]: SpecialNotifyTranslators->submitNotifyTranslatorsForm(array, HTMLForm)
#1 /var/www/mw/includes/htmlform/HTMLForm.php(443): call_user_func(array, array, HTMLForm)
#2 /var/www/mw/includes/htmlform/HTMLForm.php(385): HTMLForm->trySubmit()
#3 /var/www/mw/extensions/TranslationNotifications/SpecialNotifyTranslators.php(62): HTMLForm->tryAuthorizedSubmit()
#4 /var/www/mw/includes/specialpage/SpecialPage.php(374): SpecialNotifyTranslators->execute(NULL)
#5 /var/www/mw/includes/specialpage/SpecialPageFactory.php(491): SpecialPage->run(NULL)
#6 /var/www/mw/includes/Wiki.php(285): SpecialPageFactory::executePath(Title, RequestContext)
#7 /var/www/mw/includes/Wiki.php(586): MediaWiki->performRequest()
#8 /var/www/mw/includes/Wiki.php(447): MediaWiki->main()
#9 /var/www/mw/index.php(49): MediaWiki->run()
#10 {main}
</code>

It should be handled more gracefully.

Version: master
Severity: normal