Bug 22044: Set default and add NoRenewalBeforePrecision preference for new/affected...

Bug 22044: Set default and add NoRenewalBeforePrecision preference for new/affected installs

I am not sure the correct answer - for upgraded installs the pref was
set to date, which changed behaviour

For new installs the pref was unset, behaved as if 'exact_time' so we
shouldn't change behaviour?

If the perceived default is date then the code should be changed, or
this shouldn't be a pref at all?

To test:
1 - Have a new system missing this pref
2 - Note when searchign the pref in staff client if appears as 'date'
3 - Check the db to confirm value is 'NULL'
4 - Apply patch and run update
5 - Pref is now set to 'exact_time'

Signed-off-by: Hayley Mapley <hayleymapley@catalyst.net.nz>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>