servelog: use simplejson and the % operator for python versions < 2.6 Both the json module and str format operator are new in version 2.6, so replace them with the simplejson module and the % operator, respectively.

# Log every push and pull to the servelog

[hooks]
changegroup.aaaaa_servelog = python:mercurialserver.servelog.hook
outgoing.aaaaa_servelog = python:mercurialserver.servelog.hook