REST API: Allow unsetting of page templates in update requests.

Sending a request to update a page with the template property set to an empty string resulted in an error because “” was not a valid value in the enum.

Props lucasstark, swissspidy.
Fixes #38877.
Built from https://develop.svn.wordpress.org/trunk@39343


git-svn-id: http://core.svn.wordpress.org/trunk@39283 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php

@@ -1928,7 +1928,7 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 		$schema['properties']['template'] = array(
 			'description' => __( 'The theme file to use to display the object.' ),
 			'type'        => 'string',
-			'enum'        => array_keys( wp_get_theme()->get_page_templates( null, $this->post_type ) ),
+			'enum'        => array_merge( array_keys( wp_get_theme()->get_page_templates( null, $this->post_type ) ), array( '' ) ),
 			'context'     => array( 'view', 'edit' ),
 		);
 

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-beta4-39342';
+$wp_version = '4.7-beta4-39343';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.