[master] CQL now supports lease stat recounting

    Merges branch 'trac5487'

diff --cc src/lib/dhcpsrv/cql_host_data_source.cc
Simple merge

diff --cc src/lib/dhcpsrv/cql_lease_mgr.cc
Simple merge

diff --cc src/lib/dhcpsrv/tests/cql_lease_mgr_unittest.cc
Simple merge