Correct ignoring socket when inappropriate

When fixing the performance by declining to select() on a socket
until a recvfrom() explictly occurs to clear the socket, a problem
was injected where a socket could be made ignored by particular
timing of incoming traffic on the socket.  Correct this by having
the _poller function forcefully return True if any sockets
are ignored (which also implies they are ready since they
should be discarded on read).

Change-Id: I6be39d39e4d2ed3b05af9a4c954fb64c993ffb50

pyghmi/ipmi/private/session.py

@@ -164,8 +164,9 @@ def _monotonic_time():
 
 
 def _poller(timeout=0):
-    rdylist = _io_apply('wait', timeout + _monotonic_time())
-    return rdylist
+    if ignoresockets:
+        return True
+    return _io_apply('wait', timeout + _monotonic_time())
 
 
 def _aespad(data):
@@ -905,8 +906,7 @@ class Session(object):
                 timeout = 0
         if timeout is None:
             return 0
-        rdylist = _poller(timeout=timeout)
-        if len(rdylist) > 0:
+        if _poller(timeout=timeout):
             pktqueue = collections.deque([])
             cls.pulltoqueue(iosockets, pktqueue)
             while len(pktqueue):