Fixed unlinked refresh button for the server connection check

res/layout/account_setup.xml

@@ -65,6 +65,7 @@
                 android:layout_height="wrap_content"
                 android:layout_gravity="right|center_vertical"
                 android:src="@drawable/ic_action_refresh_black"
+            	android:onClick="onRefreshClick"
                 android:visibility="invisible" />
         </FrameLayout>
 

src/com/owncloud/android/authentication/AuthenticatorActivity.java

@@ -1006,7 +1006,7 @@ public class AuthenticatorActivity extends AccountAuthenticatorActivity
      * @param view      Refresh 'button'
      */
     public void onRefreshClick(View view) {
-        onFocusChange(mRefreshButton, false);
+        onFocusChange(mHostUrlInput, false);
     }