overlay: overlay the overlay with moar overlays

On dlx, we need to overlay our own verizon eri.xml's because these break
other devices (namely toro) by causing a roaming icon. Ours does the
opposite if we don't have them.

Also need to switch to using PRODUCT_PACKAGE_OVERLAYS instead of
DEVICE_PACKAGE_OVERLAYS and inherit it before vendor/cm/ overlays or it won't
take effect.

Change-Id: I792d6f05cc47029425c73b82afb82dc07d92f6dc

Conflicts:

	device.mk
Merge "overlay: remove eri.xml" into cm-11.0
Conflicts:

	overlay/frameworks/base/core/res/res/xml/eri.xml
Merge "overlay: overlay the overlay with moar overlays" into cm-11.0
Conflicts:

	device.mk
dlx: cleanup: remove unused files

Keylayouts/IDC: removed keylayouts and idc files that are already
provided by AOSP in frameworks/base/data/keyboards.

This makes lunch and mka ... less noisy.

Change-Id: I10cc0cb03d5c08a0e266148b5d26398f263bee19

Conflicts:

	full_dlx.mk