This has the nice side-effect of making gpsd actually run!
Old behaviour (debugLevel=2):
systemd[1]: gpsd.service holdoff time over, scheduling restart.
systemd[1]: Stopping GPSD daemon...
systemd[1]: Starting GPSD daemon...
systemd[1]: gpsd.service start request repeated too quickly, refusing to start.
systemd[1]: Failed to start GPSD daemon.
systemd[1]: Unit gpsd.service entered failed state.
New behaviour (debugLevel=2):
gpsd[945]: gpsd: launching (Version 2.95)
systemd[1]: Started GPSD daemon.
gpsd[945]: gpsd: listening on port 2947
gpsd[945]: gpsd: running with effective group ID 27
gpsd[945]: gpsd: running with effective user ID 23
gpsd[945]: gpsd: stashing device /dev/ttyUSB0 at slot 0