MFC r292759:

MFC r292759:

  Let old-style (shell-based) jail configuration handle jail names that
  contain characters not allowed in a shell variable (such as "-").
  These will be replaced by an underscore in jail config variables,
  e.g. for jail "foo-bar" you would set "jail_foo_bar_hostname".

  This is separate from the current code that changes the jail names
  if they contain "." or "/".  It also doesn't apply to jails defined
  in a jail.conf file.

PR:		191181

git-svn-id: svn://svn.freebsd.org/base/stable/10@292967 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f