If the keyspace is not present, session_ will be null and
 it would segfault in CQLConnection destructor.

# Conflicts:
#	src/lib/dhcpsrv/pgsql_lease_mgr.h

# Conflicts:
#	src/bin/admin/tests/data/pgsql.lease6_dump_test.reference.csv

# Conflicts:
#	src/bin/admin/tests/data/pgsql.lease6_dump_test.reference.csv

# Conflicts:
#	ChangeLog
#	src/lib/dhcpsrv/cfg_hosts.cc

# Conflicts:
#	ChangeLog
#	src/lib/dhcpsrv/cfg_hosts.cc

# Conflicts:
#	configure.ac

    Merges in branch 'trac4275'

bin/admin/tests/pgsql_tests.sh.in
    Typos
share/database/scripts/pgsql/.gitignore
    Added upgrade_2.0_to_3.0.sh

share/database/scripts/pgsql/dhcpdb_create.pgsql
    Added entry for client_id to hosts_identifier
    Added commentrary for dhcp_option_scope
    Added periods to the ends of sentences.

Added 4.1 to 4.2 updates from MySQL and created upgrade
script for 2.0 to 3.0

src/share/database/scripts/pgsql/dhcpdb_create.pgsql
    - Enclosed the entire script in a single transaction
    - Removed DROP TABLE statements
    - Added host_identifier_type table and data
    - Added dhcp_option_scope table and data
    - Updated unqiue constraints for hosts table
    - Added scope_id and foreign key constraint to dhcp4_options table
    - Added scope_id and foreign key constraint to dhcp6_options table
    - Added unique contraint to ipv6_reservations table
    - Changed 'HWADDR_SOURCE_DOCSIS' to 'HWADDR_SOURCE_DOCSIS_CMTS'
    - Inserted row for 'HWADDR_SOURCE_UKNOWN'

src/share/database/scripts/pgsql/dhcpdb_drop.pgsql
    Added drops for host_identifier_type and  dhcp_option_scope

src/share/database/scripts/pgsql/upgrade_2.0_to_3.0.sh.in
    New file for upgrading Postgresql from 2.0 to 3.0

configure.ac
    Added src/share/database/scripts/pgsql/upgrade_2.0_to_3.0.sh

src/bin/admin/tests/pgsql_tests.sh.in
    - pgsql_upgrade_1_0_to_2_0 - new function which contains all the checks used
    to verify 1.0 to 2.0 upgrade (extracted from pgsql_upgrade_test)
    - pgsql_upgrade_2_0_to_3_0 - new function which contains all the checks used
    to verify 2.0 to 3.0 upgrade
    - pgsql_upgrade_test() - modified use new upgrade check fucntions

src/share/database/scripts/pgsql/Makefile.am
    Added entry for upgrade_2.0_to_3.0.sh

Postresql schema now supports host reservations with options,
and lease6 table now includes hardware address and source

src/share/database/scripts/pgsql/dhcpdb_create.pgsql
    Added Schema 3.0 upgrade section:
    - new tables: hosts, dhcp4_options, dhcp6_options,
      ipv6_reservations, lease_hwaddr_source

    - lease4Dumpdata() - results now sorted by lease address

    - lease6 table - added columns hwaddr, hwtype, hwaddr_source

    - lease6DumpHeader() - added labels for new columns
    - lease6DumpData() - added new columns, results now sorted by
      lease address

    - schema_vesion - bumped version to 3

src/share/database/scripts/pgsql/dhcpdb_drop.pgsql
    Added drops of new tables

src/lib/dhcpsrv/pgsql_lease_mgr.cc
    - PgSqlLeaseMgr::PgSqlLeaseMgr() - added logic to detect schema
    mismatch between the code and configured database

src/lib/dhcpsrv/pgsql_lease_mgr.h
    - Bumped PG_CURRENT_VERSION from 2 to 3

src/bin/admin/tests/data/pgsql.lease6_dump_test.reference.csv
    - Reordered entries to account for dump function sort order
    - Added values for new columns on lease6 table

src/bin/admin/tests/pgsql_tests.sh.in
    - pgsql_lease_version_test() - changed expected version to 3.0
    - pgsql_lease6_dump_test() - added new column values to inserted rows

Decided to not move the HostTest::doExchange class to the test
utils as it would cause circular dependency.