clean up clang static analysis warnings

These were mosly just dead code. AIM_OBJECT_INIT had an unnecessary check of
whether the object was NULL, which caused clang to think that the object could
possibly be NULL, which resulted in a couple of spurious warnings in the
callers.
Merge into master from pull request #14:
clean up clang static analysis warnings (https://github.com/floodlight/infra/pull/14)