Export init.environ.rc in early-init instead of init

Now that we always have system mounted early, we're starting to load
various daemons during the `init` trigger and these daemons need the
environment set up from init.environ.rc, so we move it to early-init.

This shouldn't need to go any further earlier in the future, since
nothing besides ueventd should ever start in early-init.

Test: systems boot, early daemons get right environment
Change-Id: I02f425a1500377c5de3427afa7872073e77a066f