distros: remove leading dots in DISTRO_VERSIONs

distros: remove leading dots in DISTRO_VERSIONs

Having a leading dot in DISTRO_VERSION will result in a '-.' string when
building archive names; this may lead to mistakenly think that something is
missing in the archive name.

Example:
minimal-.dev-snapshot-20100216-i686-linux-armv5te-linux-gnueabi-toolchain.tar.bz2
       ^^

Remove the leading dot in DISTRO_VERSIONs to avoid such possible
confusion.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Acked-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>