[yocto] In consistancy in the defition of BBFILE_COLLECTIONS in layer.conf

[Jeremy Puhlman]

I was working with some layerinfo code, and I noticed that the value of
BBFILE_COLLECTIONS in layer.conf
in the meta-intel repo are kind of all over the map:

 for each in */conf/layer.conf; do cat $each; done | grep BBFILE_COLLECTIONS
BBFILE_COLLECTIONS_crownbay += "crownbay"
BBFILE_COLLECTIONS_crownbay-noemgd += "crownbay-noemgd"
BBFILE_COLLECTIONS_fishriver += "fishriver"
BBFILE_COLLECTIONS_jasperforest += "jasperforest"
BBFILE_COLLECTIONS_sugarbay += "sugarbay"

For the above layers when I just list out oe-core and one of the above,
the results from BBFILE_COLLECTIONS ends up
just being what ever was set above.

BBFILE_COLLECTIONS += "n450"
BBFILE_COLLECTIONS += "emenlow"

When using these layers, the final BBFILE_COLLECTIONS is the list of all
the layers as expected.

Was just curious if there was a intentional reason why the
difference(i.e. is there some code that I am missing that fixes this up)?

-- 
Jeremy Puhlman
Montavista Sofware, LLC.