meta-filesystems: Add LAYERVERSION and LAYERDEPENDS

According to README, it depends on oe-core and openembedded-layer

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>