Fixed issue 03994: When importing a survey with an unknown template, question preview is mixed up
Dev: Produces a warning on import but doesn't change anything so one can upload the template later. Question preview uses default tpl when it can not find the defined tpl.

git-svn-id: file:///Users/Shitiz/Downloads/lssvn/source/limesurvey@8255 b72ed6b6-b9f8-46b5-92b4-906544132732