MFC r241197:

MFC r241197:

  Fix some memory allocation errors:

  * jail_setv will leak a parameter name if jailparam_import fails.
  * jailparam_all loses the jailparam pointer on realloc error
    (a clear freshman mistake).
  * If jailparam_init fails, the caller doesn't need to jailparam_free
    the buffer.  That's not really clear, so set things to NULL allowing
    jailparam_free to work without error (though it's still not required).

git-svn-id: svn://svn.freebsd.org/base/stable/9@285343 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f