Remove non-required getter

Signed-off-by: Lukas Reschke <lukas@statuscode.ch>

lib/private/Server.php

@@ -1025,13 +1025,6 @@ class Server extends ServerContainer implements IServerContainer {
 		return $this->query('AppFetcher');
 	}
 
-	/**
-	 * @return CategoryFetcher
-	 */
-	public function getCategoryFetcher() {
-		return $this->query('CategoryFetcher');
-	}
-
 	/**
 	 * Returns an ICache instance. Since 8.1.0 it returns a fake cache. Use
 	 * getMemCacheFactory() instead.