meta-webserver: Add LAYERVERSION and LAYERDEPENDS

Add LAYERVERSION and LAYERDEPENDS to layer.conf

Signed-off-by: Wenzong Fan <wenzong.fan@windriver.com>
Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Mark Hatle <mark.hatle@windriver.com>