Fix GeventProfilingServer compatibility with gevent 1.1+.
Fix GeventProfilingServer compatibility with gevent 1.1+.

gevent's StreamServer now closes server sockets immediately after the
handler returns. Because our handler spawns its work to a greenlet, we
need to wait for the work to complete before the handler returns. This
should maintain compatibility with older versions of gevent where
StreamServer's socket closure was non-deterministic.

what-studio/profiling,what-studio/profiling