Change puppet splaylimit from 60 to 59

Internally, puppet adds 1 to the value before calling
rand(), so a splaylimit of 60 counter-intuitively ends up
giving values in the range 0-60, whereas 59 gives values of
0-59.  This eliminates (in theory) a small agent start
spike around the :00 second of every minute.

Change-Id: If217adafe308a7c895866b8075f270abde34214d