Show "refresh" instead of "start" when already encrypted.

src/templates/toolbar.html

@@ -40,7 +40,7 @@
                <li><a class="start-otr" href="#">{{label_start_encrypted_conversation}}</a></li>
             {[ } ]}
             {[ if (otr_status != UNENCRYPTED) { ]}
-               <li><a class="start-otr" href="#">{{label_start_encrypted_conversation}}</a></li>
+               <li><a class="start-otr" href="#">{{label_refresh_encrypted_conversation}}</a></li>
                <li><a class="end-otr" href="#">{{label_end_encrypted_conversation}}</a></li>
                <li><a class="auth-otr" data-scheme="smp" href="#">{{label_verify_with_smp}}</a></li>
             {[ } ]}