[#591,!#313] kea-dhcp6 skips sanity checks for prefix leases

src/lib/dhcpsrv/sanity_checker.*
    SanityChecker::checkLease(Lease6Ptr& lease, bool current) - now
    simply returns if lease type is TYPE_PD.

src/lib/dhcpsrv/tests/lease_file_loader_unittest.cc
    TEST_F(LeaseFileLoaderTest, sanityChecker6PD) - new test to
    verify PD leases are not sanity checked

ChangeLog -  added proposed entry

1 files changed, 4 insertions, 3 deletions

diff --git a/src/lib/dhcpsrv/sanity_checker.h b/src/lib/dhcpsrv/sanity_checker.h
index c181fd44c5..ad0ee24473 100644
--- a/src/lib/dhcpsrv/sanity_checker.h
+++ b/src/lib/dhcpsrv/sanity_checker.h
@@ -1,4 +1,4 @@
-// Copyright (C) 2018 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2018-2019 Internet Systems Consortium, Inc. ("ISC")
 //
 // This Source Code Form is subject to the terms of the Mozilla Public
 // License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -32,11 +32,12 @@ class SanityChecker {
     ///                config
     void checkLease(Lease4Ptr& lease, bool current = true);
 
-    /// @brief Sanity checks and possibly corrects an IPv4 lease
+    /// @brief Sanity checks and possibly corrects an IPv6 lease
     ///
     /// Depending on the sanity-checks/lease-checks parameter value (see
     /// @ref CfgConsistency for details), this code may print a warning,
-    /// correct subnet-id or discard the lease.
+    /// correct subnet-id or discard the lease.  Note that if the lease
+    /// type is TYPE_PD, it simply returns.
     ///
     /// @param lease Lease to be sanity-checked
     /// @param current specify whether to use current (true) or staging(false)