reset DB pool parameters when configuration changes, fixes #1273

git-svn-id: https://svn.qindel.com/repos/main/projects/qindel/QVD/src/trunk@19395 4046b530-fbad-4e16-af16-ee11f0b55167
use _db instead of a direct hash access to get the HKD DB pool object

git-svn-id: https://svn.qindel.com/repos/main/projects/qindel/QVD/src/trunk@19399 4046b530-fbad-4e16-af16-ee11f0b55167