[maven-release-plugin] prepare release site-2.9.1

git-svn-id: https://source.sakaiproject.org/svn/site/branches/site-2.9.x@119682 66ffb92e-73f9-0310-93c1-f5514f145a0a
[maven-release-plugin] prepare for next development iteration

git-svn-id: https://source.sakaiproject.org/svn/site/branches/site-2.9.x@119684 66ffb92e-73f9-0310-93c1-f5514f145a0a
Reverting pom back to SNAPSHOT

git-svn-id: https://source.sakaiproject.org/svn/site/branches/site-2.9.x@119716 66ffb92e-73f9-0310-93c1-f5514f145a0a