The stats page proudly displays "Updates (v1.5)". This version is inherited
from version.h which has not been updated since 1.5, so let's teach the
create-release script about it.
This must be backported to 1.7. 1.6 now uses the same script (externally)
for the release and will automatically benefit from it.
These ones have been used for several months already and are quite
convenient to emit new releases and backport fixes. I'm fed up with
having different versions on different machines, let's commit them
now.