Previously, we were using a content-type of text/directory, but that is
already defined in RFC 2425 and doesn't reflect our usage:
The text/directory Content-Type is defined for holding a variety
of directory information, for example, name, or email address,
or logo.
(From there it goes on to describe a superset of the vCard format
defined in RFC 2426.)
application/directory, on the other hand, is used by Static Web [1] and
is used by cloudfuse [2]. Seems like as sane a choice as any to
standardize on.
[1] https://github.com/openstack/swift/blob/2.5.0/swift/common/middleware/staticweb.py#L71-L75
[2] https://github.com/redbo/cloudfuse/blob/1.0/README#L105-L106
Change-Id: I19e30484270886292d83f50e7ee997b6e1623ec7
9fd537a082