Remove deprecated function checkAppEnabled

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

lib/public/App.php

@@ -94,16 +94,6 @@ class App {
 		return \OC::$server->getAppManager()->isEnabledForUser( $app );
 	}
 
-	/**
-	 * Check if the app is enabled, redirects to home if not
-	 * @param string $app
-	 * @return void
-	 * @since 4.0.0
-	 * @deprecated 9.0.0 ownCloud core will handle disabled apps and redirects to valid URLs
-	*/
-	public static function checkAppEnabled( $app ) {
-	}
-
 	/**
 	 * Get the last version of the app from appinfo/info.xml
 	 * @param string $app