WebSubmit: Set_Embargo optional and functional
- Checks if file for date exists. This allows to not meet IOError exception if the field creating the file is optional and has not been filled. (PR #2699)
- Fixes a bug where the status was set to an incorrect value.
Signed-off-by: Guillaume Lastecoueres <guillaume@tind.io>
Reviewed-by: Samuele Kaplun <samuele.kaplun@cern.ch>