bug#21112: 25; Patch: show minibuffer messages with a face

[Drew Adams]

> I'm not really convinced that there should be any face properties on the
> minibuffer messages at all, though.  :-)

Yes, and a caller can always add whatever properties
it wants/needs.  It's not hard to pass a propertized
string to `minibuffer-message'.

At any rate, if we do provide for properties in some
way, it needs to be easy for a user or calling code
to control the properties.  It not kosher to hard-code
properties for such things.