Coding Standards: Fix WPCS issues in plugin and theme upgrader classes.

See #49542.

git-svn-id: https://develop.svn.wordpress.org/trunk@47814 602fd350-edb4-49c9-b593-d223f7449a82

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

@@ -553,7 +553,7 @@ public function delete_old_plugin( $removed, $local_destination, $remote_destina
 
 		// If plugin is in its own directory, recursively delete the directory.
 		// Base check on if plugin includes directory separator AND that it's not the root plugin folder.
-		if ( strpos( $plugin, '/' ) && $this_plugin_dir != $plugins_dir ) {
+		if ( strpos( $plugin, '/' ) && $this_plugin_dir !== $plugins_dir ) {
 			$deleted = $wp_filesystem->delete( $this_plugin_dir, true );
 		} else {
 			$deleted = $wp_filesystem->delete( $plugins_dir . $plugin );

src/wp-admin/includes/class-theme-upgrader-skin.php

@@ -65,7 +65,7 @@ public function after() {
 				admin_url( 'customize.php' )
 			);
 
-			if ( get_stylesheet() == $stylesheet ) {
+			if ( get_stylesheet() === $stylesheet ) {
 				if ( current_user_can( 'edit_theme_options' ) && current_user_can( 'customize' ) ) {
 					$update_actions['preview'] = sprintf(
 						'<a href="%s" class="hide-if-no-customize load-customize">' .

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

@@ -577,7 +577,7 @@ public function current_after( $return, $theme ) {
 		}
 
 		// Ensure stylesheet name hasn't changed after the upgrade:
-		if ( get_stylesheet() === $theme && $theme != $this->result['destination_name'] ) {
+		if ( get_stylesheet() === $theme && $theme !== $this->result['destination_name'] ) {
 			wp_clean_themes_cache();
 			$stylesheet = $this->result['destination_name'];
 			switch_theme( $stylesheet );