Update hours-vs-days test

Update hours-vs-days test

This test is outdated because it tested the 'sig-validity-interval'
option that has been replaced by dnssec-policy's 'signatures-validity',
'signatures-refresh', and 'signatures-jitter' options.

Nevertheless, it tests if the jitter is spread correctly.

Update the test to make use of 'signatures-jitter', set the value
to 1 day (meaning resign in 499 days since 'signatures-validity' is
set to 500 days).

Note that this previously changed erroneously the refresh value to
449 days (should have been 499 days, but that is not allowed by
checkconf, since it is above 90% of 'signatures-validity').