Kernel build failure when INET6 not defined

[Matthew Dillon]

:If you compile a kernel with INET6 *not* defined, you will get the following
:failure:
:...
:
:This appears to be a new problem introduced by rev 1.14 of kern/kern_jail.c.
:
:The following patch (also attached to preserve whitespace) fixes the problem
:by wrapping the INET6-specific code with the proper #if check.

    It looks like that piece of code has other bugs as well, like defaulting
    out to the assumption of INET6.  I'll get a fix for both bugs committed
    in a moment.

					-Matt