Standardize the login form button text

The default always seemed to be connect, potentially
due to a bug. This just gets rid of the connect option
and makes 'sign in' the only text.

Closes-bug: #1767021
Change-Id: I77830ddb24616742abe691b45f89b8c9eb18aff9

horizon/templates/auth/_login_form.html

@@ -75,8 +75,7 @@
     <div class="panel-footer">
       {% block login_footer %}
         <button id="loginBtn" type="submit" class="btn btn-primary pull-right">
-          <span ng-show="auth_type==='credentials'">{% trans "Sign In" %}</span>
-          <span ng-hide="auth_type==='credentials'" ng-cloak>{% trans "Connect" %}</span>
+          <span>{% trans "Sign In" %}</span>
         </button>
         <div class="clearfix"></div>
       {% endblock %}