ensure git command calls always have exit status 0

setversion.sh tries to embed either a git revision, or "tarball", in Version.vb

If git is not installed, or you are building from a non-git tree (e.g. a tarball) then the git commands fail, causing the script to bail out - thus the "tarball" version can never be set.

This patch calls "true" immediately after "git", so the exit status is always 0, and the script carries on normally