webadmin: new pool dialog should not contain Blank template

This regression has been introduced by:
604d22dc036d1f5a4431c8247ce246d0c0a0c109

Fixed by moving back the code to filter out the Blank template from the new
pool dialog.

Change-Id: I6acdd3427e5c11b854bfd4c9c209c55da12b88a5
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1066646
Signed-off-by: Tomas Jelinek <tjelinek@redhat.com>