Upgrade maven plugins

exec-maven-plugin 1.2 -> 1.2.1
clirr-maven-plugin 2.2.3 -> 2.5
maven-eclipse-plugin 2.6 -> 2.9
maven-surefire-plugin 2.7.2 -> 2.13
findbugs-maven-plugin 2.3.1 -> 2.5.2

git-svn-id: https://svn.apache.org/repos/asf/shindig/trunk@1534017 13f79535-47bb-0310-9956-ffa450edef68