all: Remove the never released MooseFS 1.7 quotas

A simple quota system was planned for MooseFS 1.7 and partially
implemented in MooseFS 1.6, the direct ancestor of LizardFS.

However, LizardFS isn't going to use this implementation so we
are dropping it.

Change-Id: I0d28cbedd4e5832dcb96681f6da10d557e6a6bd6