client/dhclient.c
    minor change to add_to_tail()

Added a release note.

client/clparse.c
    parse_client_lease_statement () - now calls new discard_duplicate()
    function. This avoids discarding config file leases that match
    lease file leases

client/dhclient.c
    discard_duplicate() - new function that removes a lease from a list
    of leases that matches a given lease, both by address and source

    add_to_tail() - new function that adds a given lease to the end of
    a linked list of leases, removing any duplicates from the list first.

    bind_lease() - if the active lease being replaced by the new
    lease is a fallback lease, then we move it the end of
    client->leases, rather than discard it.

    state_panic() -  now calls add_to_tail() to move the
    active lease that just failed to the end of client->leases.
    This ensures that we keep only the most recent versions of
    dynamic leases.

Added comments on #endif statements

Added a release note.

client/dhclient.c
    Only include dhclient_ddns_cb_free() if NSUPDATE is defined

includes/omapip/isclib.*
    Only inlucde isc_result_t dns_client_init() if NSUPDATE is defined

    Merges in rt46957

    Merges in rt46805.

   Merges in rt23252a.

    Merges in rt46836

    Merges in rt22675.

    Merges in rt23252.

    Merges in rt21237

    Merges in rt2729.

    Merges in rt46535

    Merges in rt45457

    Merges in rt43792

    Merges in rt46616.

    Merges in 46332.

    Merges rt31573.

    Merges in rt18183a.

# Conflicts:
#	client/scripts/linux

    Merges in rt44373.

    Merges in rt41185.

    Merges in rt45290.

    Merged #36169

    Merges in rt41473.

    Merged rt43326.