package_deb.bbclass: make version acceptable for dpkg-deb.

package_deb.bbclass: make version acceptable for dpkg-deb.

dpkg-deb does not like version numbers without digits:

NOTE: Running task 428 of 604 (ID: 14,
	[...]/openembedded/recipes/linux-firmware/linux-firmware_git.bb,
	do_package_write_deb)
dpkg-deb - error: (upstream) version (`git') doesn't contain any digits
dpkg-deb: 1 errors in control file
NOTE: package
	linux-firmware-git-r1+gitr2fab48391fda8a914b55c8ac265eb3b6ee10ace8:
	task do_package_write_deb: Started

This commit causes version numbers without digits to be appended with '0':
linux-firmware-agere_git0-r1+gitr2fab48391fda8a914b55c8ac265eb3b6ee10ace8_all.deb

Signed-off-by: Filip Zyzniewski <filip.zyzniewski@gmail.com>
Signed-off-by: Tom Rini <tom_rini@mentor.com>