[master] Merge branch 'trac4489'

diff --cc doc/Makefile.am
Simple merge

diff --cc doc/guide/admin.xml
Simple merge

diff --cc doc/guide/dhcp4-srv.xml
Simple merge

diff --cc doc/guide/dhcp6-srv.xml
Simple merge

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

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

diff --cc src/lib/dhcpsrv/tests/generic_host_data_source_unittest.h
Simple merge

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

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