Exclude fuse-extra from project.clj

We just noticed that the latest version of activemq is dragging in
a new dependency: `org.fusesource.fuse-extra/fusemq-level`.
This new dependency doesn't seem to be used (need to test that theory!)
and adds 20MB of bloat to our uberjar.
Merge pull request #403 from cprice-puppet/maint/master/exclude-fusesource

Exclude fuse-extra from project.clj