In a middle-layer method for returning holdable formats on a metarecord,

In a middle-layer method for returning holdable formats on a metarecord,

Do a better test of copy holdability than we were doing previously.
We can't do a perfect test: we don't really know what patron we're doing
this for, and even if we did, from here it's nontrivial to figure out
whether we're doing indb holds or script-based, much less run the tests.

Still, we can test whether a copy's in a holdable status, a holdable
location, and is itself not explicitly marked unholdable.

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>