OMP::CGIPage::PkgData: remove extension for CADC

For the list of file names being posted to CADC's download
manager, remove the .sdf filename extensions as requested
by JJ:

Date:   Wed, 13 Aug 2014 12:18:22 -0700
From:   Kavelaars, JJ <JJ.Kavelaars@nrc-cnrc.gc.ca>

Can someone there check that the URIs that are being sent to
/en/download from OMP are do NOT have the .sdf extension.