Properly configure visibility of spoiler toolbar button

src/templates/toolbar.html

@@ -3,7 +3,7 @@
     <ul class="emoji-picker"></ul>
 </li>
 {[ } ]}
-{[ if (o.allow_spoiler_messages) { ]}
+{[ if (o.show_spoiler_button)  { ]}
 <li class="toggle-spoiler-edit">
     <a class="
         {[ if (o.sending_spoiler)  { ]} icon-eye-blocked {[ } ]}