LP#1205492: fix crash when attempting to renew deposit & rental loans in OPAC

LP#1205492: fix crash when attempting to renew deposit & rental loans in OPAC

This patch fixes a bug where attempting to renew a loan on an item
that requires a deposit or a rental fee can cause an Apache
internal server error.

In particular, this patch supplies descriptions for the following
events:

  ITEM_DEPOSIT_REQUIRED
  ITEM_RENTAL_FEE_REQUIRED
  ITEM_DEPOSIT_PAID

It also normalizes how 'fail_part' is set in the renewal response,
as the payload of an event returned when a renewal fails can
be either a hash or an acp Fieldmapper object depending on the
type of event.  In the former case, attempting to access an
nonexistent ->fail_part method is what causes the crash.

To test
-------
[1] Create an item that requires a deposit or a rental fee
    and check it out.
[2] Attempt to renew the loan in the public catalog. Note
    that an internal server error is returned.
[3] Apply the patch and attept step 2 again. This time, the
    public catalog should display a notification to the patron
    that the renewal cannot take place, rather than crashing.
[4] Set up other situations where a renewal should fail for
    reasons other than a deposit/rental fee being required. Verify
    that appropriate error messages are displayed in the public
    catalog.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Mike Rylander <mrylander@gmail.com>