Coding Standards: Explicitly declare the $wp_version global used in some core files.

Props jaydeep-rami, sabernhardt.
Fixes #44932.

git-svn-id: https://develop.svn.wordpress.org/trunk@48971 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-plugin-upgrader.php

@@ -406,13 +406,14 @@ class Plugin_Upgrader extends WP_Upgrader {
 	 * @since 3.3.0
 	 *
 	 * @global WP_Filesystem_Base $wp_filesystem WordPress filesystem subclass.
+	 * @global string             $wp_version    The WordPress version string.
 	 *
 	 * @param string $source The path to the downloaded package source.
 	 * @return string|WP_Error The source as passed, or a WP_Error object
 	 *                         if no plugins were found.
 	 */
 	public function check_package( $source ) {
-		global $wp_filesystem;
+		global $wp_filesystem, $wp_version;
 
 		$this->new_plugin_data = array();
 
@@ -459,7 +460,7 @@ class Plugin_Upgrader extends WP_Upgrader {
 			$error = sprintf(
 				/* translators: 1: Current WordPress version, 2: Version required by the uploaded plugin. */
 				__( 'Your WordPress version is %1$s, however the uploaded plugin requires %2$s.' ),
-				$GLOBALS['wp_version'],
+				$wp_version,
 				$requires_wp
 			);