MFC r227893 and r228119:

MFC r227893 and r228119:

  Avoid double free creating a new RAID with invalid command line
  arguments.

  In build_volume(), check if arrays is allocated before traversing its
  items.  While parsing the arrays input, it's possible that we reach the
  error path before initializing the 'arrays' pointer, which in turn leads
  to a NULL deference.

git-svn-id: svn://svn.freebsd.org/base/stable/8@231113 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f