(PUP-3702) roll-back previous fix, which broke solaris11 zone acceptance

Inherit /sbin in the zone acceptance tests on solaris10 until PUP-3722.
Solaris10 zone provider needs to add /sbin to it's pkg-dir inheritance
otherwise the zones cannot boot.  solaris11 zones can not be configured
with inherit-pkg-dir because of IPS.  this is covered by PUP-3722.