Bug 7583 follow-up: Prevent users to cancel receipt if they can't

Bug 7583 follow-up: Prevent users to cancel receipt if they can't

Disable the link for cancelling instead of displaying an error message
after the click. This is only valid if parent order line is received,
not if it's deleted.
When the user gets his mouse over the disabled link, he gets a message
telling him which order (ordernumber) blocks him so he knows immediately
which receipt to cancel.
Also improve error messages for non technical people

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>