/src: commit with -n in release.sh scripts

As *requested* by @sschuberth in msysgit/msysgit#169 I changed all `src/\<package\>/release.sh` to
use `commit -n`.
While doing that I noticed that some packages cannot be built (e.g. zlib-1.2.7.tar.gz doesn't exist).
If I find some time I'll try to fix some of them....later.

This PR is on top of my `sn/vim74`. If that's not OK, just tell me.