Sonar clean-ups

Sonar clean-ups

Starting from source files containing collapsible ifs:
* merge collapsible ifs;
* remove unused parameters;
* remove unused exceptions;
* remove unused fields;
* rename shadowing variables;
* add private constructors for utility classes;
* use more specific exceptions than RuntimeException;
* clean up "if () return true; else return false;";
* some Java 7 <> operators;
* add missing "static" for constants;
* remove unused private methods (except in OF13Provider);
* move some inline comments above the corresponding source line;
* used boolean instead of Boolean for Map::contains();
* replace foreach-style constructs examining the first element only
  with explicit "if (...hasNext()) ... = ... next()";
* prohibit overriding methods called from constructors;
* remove useless casts.

Reverse the order of node augmentation handling in SouthboundUtil so
that the augmentation case can actually trigger.

Change-Id: Ie4fc662bdcc0e2133fdd4f57b783723466b1f2a9
Signed-off-by: Stephen Kitt <skitt@redhat.com>