UploadableListener::moveFile - info['fileWithoutExt'] fix

When using relative path in entity, something like this 
/**
 * @ORM\Entity
 * @Gedmo\Uploadable(appendNumber=true, path="./uploads", filenameGenerator="ALPHANUMERIC")
 */
and filename had no extension then filename generated was just "-2"

i've written a test and fixed it