sys-apps/iproute2: remove redundant patch

As of iproute2-3.7.0 this patch is no longer needed.

Now that there are no patches we can also remove the custom environment
that injects epatch_user.
sys-devel/gettext: remove redundant patch

As of gettext-0.18.2 no custom patch is needed.  This means we can also
remove the custom environment.