ls: fix a --color regression from r337956

ls: fix a --color regression from r337956

The regression is in-fact that I flipped the default from never to auto. The
incorrect impression was based on an alias that I failed to notice,
installed by the Linux distribution that I used for testing compatibility
here. Users that want the old default should be doing so with a shell alias
as is done elsewhere, rather than making this decision in ls(1).

Many thanks to rgrimes for pointing out the alias that I clearly overlooked
that resulted in this; if you despised colors in your terminal from this,
consider buying him a beer at the next venue that you see him at.

MFC after:	1 week
Relnotes:	yes