ThreadGroup remove unused name parameters

Thread/ThreadGroup constructors take a name parameter which is never
used, so we can simplify things a bit by removing it.  If anything is
referencing the internal self.name it should be using its own
name->threadgroup mapping (e.g via a dict or similar container class)

Change-Id: I6877a2fcee60ce9fc087d38aa492d7c9d50ce97e
Signed-off-by: Steven Hardy <shardy@redhat.com>
Merge "ThreadGroup remove unused name parameters"