adding handling EINTR to poll to make it more robust

some system call and signal will interrupt poll,
making event loop stops and fails to react events and keepalive message
from libvirt.
adding handling EINTR to poll to make it more robust
Signed-off-by: NRoyce Lv <lvroyce@linux.vnet.ibm.com>

examples/domain-events/events-python/event-test.py

@@ -178,6 +178,7 @@ class virEventLoopPure:
     def run_once(self):
         sleep = -1
         self.runningPoll = True
+        try:
             next = self.next_timeout()
             debug("Next timeout due at %d" % next)
             if next > 0:
@@ -212,13 +213,17 @@ class virEventLoopPure:
                     continue
 
                 want = t.get_last_fired() + interval
-            # Deduct 20ms, since schedular timeslice
+                # Deduct 20ms, since scheduler timeslice
                 # means we could be ever so slightly early
                 if now >= (want-20):
                     debug("Dispatch timer %d now %s want %s" % (t.get_id(), str(now), str(want)))
                     t.set_last_fired(now)
                     t.dispatch()
 
+        except (os.error, select.error), e:
+            if e.args[0] != errno.EINTR:
+                raise
+        finally:
             self.runningPoll = False