Fix runtime warning in ctkDICOMTableView
Fix runtime warning in ctkDICOMTableView

This commit avoid message "QSqlQuery::exec: database not open" to be
reported when the ctkDICOMBrowser is instantiated.

Fixes the message reported when running ctkDICOMBrowserTest1.

151706061/CTK,AndreasFetzer/CTK,ddao/CTK,CJGoch/CTK,SINTEFMedtek/CTK,151706061/CTK,SINTEFMedtek/CTK,commontk/CTK,SINTEFMedtek/CTK,Sardge/CTK,jcfr/CTK,ddao/CTK,CJGoch/CTK,151706061/CTK,naucoin/CTK,commontk/CTK,ddao/CTK,151706061/CTK,AndreasFetzer/CTK,jcfr/CTK,naucoin/CTK,CJGoch/CTK,ddao/CTK,Sardge/CTK,151706061/CTK,CJGoch/CTK,CJGoch/CTK,AndreasFetzer/CTK,jcfr/CTK,Sardge/CTK,SINTEFMedtek/CTK,jcfr/CTK,naucoin/CTK,jcfr/CTK,naucoin/CTK,commontk/CTK,commontk/CTK,SINTEFMedtek/CTK,Sardge/CTK,AndreasFetzer/CTK