Empty directory in octave-image package source

[Rafael Laboissière <rafael@debian.org>]

Lintian reports [*] three strange issues with the octave-image package 
(version 2.8.0-1, recently uploaded to unstable):

P: octave-image source: source-contains-empty-directory inst/@strel/
P: octave-image source: source-contains-empty-directory inst/private/
P: octave-image source: source-contains-empty-directory src/m4/

Those three directories are not empty in the upstream tarball.  I have no 
clue about what is going on.  Could someone investigate this, please?

Best,

Rafael

[*] https://lintian.debian.org/full/team+pkg-octave-team@tracker.debian.org.html#octave-image