Updating mvn release plugin and git scm versions

release:prepare is making changes and adding them to the git index but
not committing them; trying the update fix mentioned in

http://stackoverflow.com/questions/15166781/mvn-releaseprepare-not-committing-changes-to-pom-xml
[maven-release-plugin] prepare release 0.4.3
[maven-release-plugin] prepare for next development iteration
Add explicit git ref fetch in gh-pages-update.sh