Prevent renewal of an item which has a hold placed on it

Prevent renewal of an item which has a hold placed on it

Per http://biblio.laurentian.ca/tickets/conifer/wiki/devHolds, we had
this functional in 1.6 but must not have had the updated script checked
into SVN (now git) for the purposes of our upgrade, as the functionality
is not present after our upgrade.

Adding this to the repo so that we can test and hopefully get rid of the
regression.

Signed-off-by: Dan Scott <dscott@laurentian.ca>