Revert "propagate a groups through 411 only if GID > 500"

This can cause problem with system group which are inconsistent
across the different nodes. For the moment we prefer to leave the
default behaviour (aka how it was working before): all the groups
are pushed to the nodes.

This reverts commit b211af9a69714a6ec9e0f8a7b6bbf6f5daac6c46.