Fix failing opencv package due to runtime package dependency

Fix failing opencv package due to runtime package dependency

meta-openembedded merged http://cgit.openembedded.org/meta-openembedded/commit/?h=pyro&id=38b82e7794a90641beef4b6ee648317d058572f8
which led to the creation of an empty package but the runtime-requirement ended up in the rpm.
This broke image creation due to a unavailable runtime dependency on libopencv-ts (which is empty).
Temporarily pin meta-openembedded until fixed upstream.

Bug-AGL: SPEC-971

Change-Id: Idd5234719e0d52833ae86ead0e053621f6a52ea7
Signed-off-by: Jan-Simon Möller <jsmoeller@linuxfoundation.org>