Use of wp_nav_menu_disabled_check() makes BP 1.9. non compatible to WP < 3.6.

[lenasterg]

Hi.
In the bp-core/admin/bp-core-functions.php line 748 the use of wp_nav_menu_disabled_check() which is introduced in WP at version 3.6, breaks the 'Appearance->Menu" page if it used in an WP <3.6.

I think either

• "Requires at least: 3.5" should be changed

or

• if it doesn't break much of a functionality to add a function_exists() check on bp-core/admin/bp-core-functions.php line 744.

<?php if (function_exists(wp_nav_menu_disabled_check)) { ?>
                        <p class="button-controls">
			<span class="add-to-menu">
				<input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button-secondary submit-add-to-menu right" value="<?php esc_attr_e( 'Add to Menu' ); ?>" name="add-custom-menu-item" id="submit-buddypress-menu" />
				<span class="spinner"></span>
			</span>
                </p>
                    <?php } ?>

[boonebgorges]

In 7827:

On Appearance > Menus, only call wp_nav_menu_disabled_check() if the function exists

It was introduced in WP 3.6.

Fixes #5381

Props lenasterg