Address FindBugs issues and disable some detectors

This commit fixes enough FindBugs issues and disables enough detectors for `mvn findbugs:check` to pass.
If the previous code already does nothing, I would simply be tempted to update this PR to simply remove

https://github.com/andrewgaul/jclouds/blob/findbugs/providers/gogrid/src/main/java/org/jclouds/gogrid/compute/options/GoGridTemplateOptions.java#L55-L60