Multi-select explorer action on Windows defaults FILEOPEN 2 different
ODF file type documents as template - e.g. opening two different type
of files (ie : ODS & ODF) then doesn't keep the original filenames.

So now changing the open command for the different file extensions to
the same one "soffice.exe -o %1", will keep the names of the _2_ files
as they originally are when they are opened together.

Change-Id: I2cd5fcb046f294742e59f69b7bf2a897a6ce0c29
Reviewed-on: https://gerrit.libreoffice.org/36995Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>