Fix reported file time for clock reports
Fix the format specification for clock tables.
Niels writes:
Bernt was right in that there were more arguments to format than the
format string specified. I guess I must not have noticed that there was
a call to format (all the other times properties columns are 'maybe
inserted' go directly to `insert-before-markers'), and I must have
forgotten to test the multifile case (I never used multifile clock
reports myself).
However, to keep the layout of the table consistent the *File time*
cells should be in the Headline column. Attached patch fixes this by
putting the (empty) properties cells *before* the *File time* cell.