opstate RESTful API implementation with unit test application

Signed-off-by: Babu Shanmugam <anbu@enovance.com>
changes to accomodate review comments on previous version

Signed-off-by: Babu Shanmugam <anbu@enovance.com>
Merge remote-tracking branch 'enovance/wip-rgw-geo-2-opstate' into wip-rgw-geo-2

Conflicts:
	src/Makefile.am
	src/rgw/rgw_admin.cc
	src/rgw/rgw_common.h

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw-admin: restructure replicalog commands

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: initialize sent_header in RGWOp_Opstate_List

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>