MB-5307: improved typespec of ns_memcached:create_new_checkpoint
MB-5307: improved typespec of ns_memcached:create_new_checkpoint

Change-Id: Id4985ed2f60823ea2ef9ebcd1867c637440daeb5
Reviewed-on: http://review.couchbase.org/19343
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>
Tested-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

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