BOARD_USES_PRODUCT_SERVICES_IMAGE => BOARD_USES_PRODUCT_SERVICESIMAGE

This is the name used by envsetup.sh.

Test: `m init.environ.rc` and see directory
$OUT/root/product-services and see symlink $OUT/system/product-services

Change-Id: Ie615b6d76e2c60e6472900c33d9a87cfe99c4064