webos.inc: Override OPKGLIBDIR instead of opkglibdir

[GF-5571] CCC: Upgrade to Yocto 1.4 Dylan

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I8da34c922fc43ff6e3a482da65d41d6d947cf083
Reviewed-on: https://g2g.palm.com/2213
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>