Updated layman.add and layman.delete to adjust make.conf
Updated layman.add and layman.delete to adjust make.conf

When the first overlay is added, the make.conf needs to source layman's
make.conf so that emerge sees the packages in the overlay. Likewise,
when the last overlay is deleted, the make.conf needs to no longer
source layman's make.conf as it will cause emerge to break.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt