Add initialization in calendar_time's constructor.
Add initialization in calendar_time's constructor.

gintenlabo/jubatus_core,rimms/jubatus_core,kumagi/jubatus_core,rimms/jubatus_core,gintenlabo/jubatus_core,kumagi/jubatus_core,rimms/jubatus_core,kumagi/jubatus_core,kumagi/jubatus_core,gintenlabo/jubatus_core,rimms/jubatus_core,gintenlabo/jubatus_core