Currently we check the age of the primary Fernet key on Keystone
startup, and fail if it is older than the rotation interval. While this
may seem sensible, there are various reasons why the key may be older
than this:
* if the rotation interval is not a factor of the number of seconds in a
week, the rotation schedule will be lumpy, with the last rotation
being up to twice the nominal rotation interval
* if a keystone host is unavailable at its scheduled rotation time,
rotation will not happen. This may happen multiple times
We could do several things to avoid this issue:
1. remove the check on the age of the key
2. multiply the rotation interval by some factor to determine the
allowed key age
This change goes for the more simple option 1. It also cleans up some
terminology in the keystone-startup.sh script.
Closes-Bug: #1895723
Change-Id: I2c35f59ae9449cb1646e402e0a9f28ad61f918a8