olsr: update hash source comment

Commit ec9e34c9 (olsr: bump version, 2015-07-14) update the hash but left
the old source comment. Fix this.

Cc: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>