CBD-399: remove unused function in XDCR checkpoint code
CBD-399: remove unused function in XDCR checkpoint code

Change-Id: Ief77c8749412dfc3130e77e6afb1a2012c8e5599
Reviewed-on: http://review.couchbase.org/18710
Tested-by: Junyi Xie <cec9b1c9f34a8d92cba938f3f3364d5120580782@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Junyi Xie <cec9b1c9f34a8d92cba938f3f3364d5120580782@gmail.com>

pavel-blagodov/ns_server,ceejatec/ns_server,mschoch/ns_server,vzasade/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server,daverigby/ns_server,mschoch/ns_server,t3rm1n4l/ns_server,membase/ns_server,nimishzynga/ns_server,ceejatec/ns_server,mschoch/ns_server,ceejatec/ns_server,nimishzynga/ns_server,membase/ns_server,membase/ns_server,mschoch/ns_server,mschoch/ns_server,nimishzynga/ns_server,membase/ns_server,vzasade/ns_server,ceejatec/ns_server,pavel-blagodov/ns_server,membase/ns_server,ceejatec/ns_server,nimishzynga/ns_server,membase/ns_server,mschoch/ns_server,nimishzynga/ns_server,daverigby/ns_server,pavel-blagodov/ns_server,vzasade/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,daverigby/ns_server,daverigby/ns_server,vzasade/ns_server,t3rm1n4l/ns_server,daverigby/ns_server,t3rm1n4l/ns_server