Floating reservation may be incorrectly re-used if release on disconnect leeway is zero

When leeway is configured as zero, in theory a following sequence may happen with tight enough timing:

• Client1 has previously made a process based floating reservation
• Client1 disconnects
• Client2 connects
• Licenser handles Client1 disconnection, this emits an immediate leeway_expired event
• Client2 connection is next event to be handled in the queue
  • allows re-usage of the Client1 reservation
• leeway_expired is the next event in queue
  • skip release because Client2 is now connected to reservation

The expected result when leeway is zero, is that no re-use of a process based floating reservation should occur.