fix facets add/update

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1580687 13f79535-47bb-0310-9956-ffa450edef68
use an utility methods to prevent npe when column values does not exist for a row

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1580688 13f79535-47bb-0310-9956-ffa450edef68
add NPE check

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1580689 13f79535-47bb-0310-9956-ffa450edef68