opscode-cookbooks/maven — pull request #45 by peterabbott (2014-08-24 16:26:22+00:00)
Title: check if M2_HOME or MAVEN_OPTS has already been set before setting. 

This will allow users/scripts to use a different version of Maven if required. The current setup will force you to the default installed version unless MAVEN_SKIP_RC is set. This seems a pain if all you want to do is override one or the other setting.