MFC r293028,r293029:

MFC r293028,r293029:

r293028:

- Use geom <class> load instead of g<class> load; g<class> doesn't exist
  for all geom classes, e.g. geom_uzip(4)
- These tests require root. Skip all of the tests if they're run as non-root

r293029:

Add functions for managing md(4) devices and cleaning up said md(4) devices

These will be used soon in the various test scripts that source geom_subr.sh

git-svn-id: svn://svn.freebsd.org/base/stable/10@294063 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f