Bug 28372: Use variables instead of repeated field lookup

Bug 28372: Use variables instead of repeated field lookup

This simply replaces repeated lookups of the field with a variable test

To test:
1 - Perform a search on the staff client
2 - Note the 'Format' in the  record results
3 - Apply patch
4 - Repeat search
5 - Confirm Formats are unchanged

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>