Edit heartbeat_interval variable to accept integer instead of time

[aaronreay]

Within /etc/bareos/bareos-dir.d/director/bareos-dir.conf, Heartbeat Interval accepts a value of an integer E.G 60. However, when attempting to set a value of 60 within the bareos director configuration, the below error is shown during rspec testing

Value '60' does not match regex (?i-mx:^(\d+|(\d+\W+(seconds|sec|s|minutes|min|hours|h|days|d|weeks|w|months|m|quarters|q|years|y)\W*)+)$)

class { 'bareos::director::director':
  heartbeat_interval      => 60
...
}

Where 60 is a valid value for the bareos-dir.conf heartbeat_interval. The values matched by Puppet's timestamp will not work here.