Turn EAGAIN warning into debug (#629)

It can be super verbose, let's keep it but reduce from warning.

datadog/dogstatsd/base.py

@@ -609,7 +609,7 @@ def _xmit_packet(self, packet, is_telemetry):
             self.close_socket()
         except socket.error as se:
             if se.errno == errno.EAGAIN:
-                log.warning("Socket send would block: {}, dropping the packet".format(se))
+                log.debug("Socket send would block: %s, dropping the packet", se)
             else:
                 log.warning("Error submitting packet: {}, dropping the packet and closing the socket".format(se))
                 self.close_socket()

tests/unit/dogstatsd/test_statsd.py

@@ -383,8 +383,8 @@ def test_socket_overflown(self):
         with mock.patch("datadog.dogstatsd.base.log") as mock_log:
             self.statsd.gauge('no error', 1)
             mock_log.error.assert_not_called()
-            c = [call("Socket send would block: Socket error, dropping the packet")]
-            mock_log.warning.assert_has_calls(c * 2)
+            c = [call("Socket send would block: %s, dropping the packet", mock.ANY)]
+            mock_log.debug.assert_has_calls(c * 2)
 
     def test_distributed(self):
         """