Make the default Trigger hibernation 3 minutes instead of 5 seconds

The min() vs max() fix in D17560 meant that the Trigger daemon only
hibernates for 5 seconds, so we do a full GC sweep every 5 seconds. This ends
up eating a fair amount of CPU for no real benefit.

The GC cursors should move to persistent storage, but just bump this default
up in the meantime.

Auditors: chad