Merge "rdbms: make selectRowCount() use $var argument to exclude NULLs"

diff --cc includes/libs/rdbms/database/DBConnRef.php
Simple merge

diff --cc includes/libs/rdbms/database/Database.php
Simple merge

diff --cc includes/libs/rdbms/database/DatabaseMysqlBase.php
Simple merge

diff --cc includes/libs/rdbms/database/DatabasePostgres.php
Simple merge

diff --cc includes/libs/rdbms/database/IDatabase.php
Simple merge