Fix session reuse stall for async usage

Previously, calling code had to manually force an event loop iteration
after making an asynchronous session creation request.  Address that
by making a non blocking iteration request happen automatically.

Change-Id: I64f814401cb5ac397ac9ca4a1ae1d434976a2b01

pyghmi/ipmi/private/session.py

@@ -318,6 +318,9 @@ class Session(object):
                     self.logonwaiters.append(onlogon)
                 else:
                     self.iterwaiters.append(onlogon)
+            # Induce an immediate iteration of the event loop
+            # so that these handlers get the information they are hoping for
+            Session.wait_for_rsp(0)
             return
         self.maxtimeout = 3  # be aggressive about giving up on initial packet
         self.incommand = False