Cancel requests via RequestId in NCIP::ILS::Evergreen.

Cancel requests via RequestId in NCIP::ILS::Evergreen.

Add a routine to search for holds via the RequestIdentifierValue of
the CancelRequestItem message's RequestId.  This searches action::
hold_request_note by title and body for  uncancelled, unfilled holds
where request_lib is equal to our working org. unit.  If found, the
corresponding hold is returned to be canceled.

The original logic of searching by ItemId remains as a fallback
when the above fails and for those cases where holds were placed
before this logic was added.

Signed-off-by: Jason Stephenson <jstephenson@mvlc.org>