testsuite: Fix notify test no not fail on the 30th

testsuite: Fix notify test no not fail on the 30th

We are setting the month property to 10 different values,
checking that the change succeeds. But the calendar defaults
to the current date, so on every 30th of the month, we
try to set a date of Febuary 30, which fails.

Lets fix this before the 31st, by setting the calendar
to a good date.