The (global) schedule can be configured in "gerrit.config" by specifying
startTime and interval. The "startTime" can be specified in section "gc"
in the following format:
startTime = <hours>:<minutes>
or
startTime = <day of week> <hours>:<minutes>
The "interval" can be given using the usual time unit suffixes.
Change-Id: I16e92c353d0fa05c020fc18da4ed1f5825ad677c