Fixes issue introduced in 482f166 where the tracer spams when unconfigured.
Fixes issue introduced in 482f166 where the tracer spams when
unconfigured.

In the aforementioned commit, the existing behavior was changed,
I believe in advertantly, to set propagate to False if the
trace logger already has been configured. This seems to be the
opposite of the internet, and this change restores what appears
to have been the intent, and silences the tracer unless
it has been configured, in which case it will propagate.

AlexMaskovyak/elasticsearch-py,tailhook/elasticsearch-py,prinsherbert/elasticsearch-py,gardsted/elasticsearch-py,liuyi1112/elasticsearch-py,veatch/elasticsearch-py,mjhennig/elasticsearch-py,brunobell/elasticsearch-py,brunobell/elasticsearch-py,elastic/elasticsearch-py,kelp404/elasticsearch-py,elastic/elasticsearch-py,Garrett-R/elasticsearch-py,chrisseto/elasticsearch-py,thomdixon/elasticsearch-py