Bug 20996: (follow-up) Fix column name expectation

Bug 20996: (follow-up) Fix column name expectation

This bug changes how request metadata is obtained. Previously the
appropriate backend's metadata function would return it. For at least
the FreeForm backend, the metadata property names we title cased. The
datatable JS was expecting this and breaks with the new metadata getting
which is performed in the API controller, which just returns the
property names as they appear in the DB.

This patch changes the expectation of the JS to match what's coming back
from the API

Signed-off-by: Magnus Enger <magnus@enger.priv.no>
Tested by repeatedly loading the API-call
http://intranet/api/v1/illrequests?embed=metadata,patron,capabilities,library
in Chromium and watching the reported time to load the URL. There
is a siginificant decrease in the time with the patches compared to
the time it takes without the patches. I had some concerns along the
way, but they have all been fixed.

Signed-off-by: Magnus Enger <magnus@libriotech.no>
Tested by repeatedly loading the API-call
http://intranet/api/v1/illrequests?embed=metadata,patron,capabilities,library
in Chromium and watching the reported time to load the URL. There
is a siginificant decrease in the time with the patches compared to
the time it takes without the patches. I had some concerns along the
way, but they have all been fixed.

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>