Merge pull request adafruit#87 from DynamicDevices/ajl/fix-multiple-pingreqs

adafruit_minimqtt: Fix issue adafruit#86 with multiple poll() PINGREQs

Author: brentru

adafruit_minimqtt/adafruit_minimqtt.py

@@ -776,13 +776,13 @@ def loop(self, timeout=1):
             self._timestamp = time.monotonic()
         current_time = time.monotonic()
         if current_time - self._timestamp >= self.keep_alive:
+            self._timestamp = 0
             # Handle KeepAlive by expecting a PINGREQ/PINGRESP from the server
             if self.logger is not None:
                 self.logger.debug(
                     "KeepAlive period elapsed - requesting a PINGRESP from the server..."
                 )
             rcs = self.ping()
-            self._timestamp = 0
             return rcs
         self._sock.settimeout(timeout)
         rc = self._wait_for_msg()