Revert "serial.write should have a blocking wait if the serial port is busy"

This reverts commit 0537d1fcac.

platypush/plugins/serial/__init__.py

@@ -131,7 +131,9 @@ class SerialPlugin(GpioSensorPlugin):
         if isinstance(data, str):
             data = data.encode('utf-8')
 
-        with self.serial_lock:
+        try:
+            serial_available = self.serial_lock.acquire(timeout=2)
+            if serial_available:
                 try:
                     ser = self._get_serial()
                 except:
@@ -140,6 +142,8 @@ class SerialPlugin(GpioSensorPlugin):
 
                 self.logger.info('Writing {} to {}'.format(data, self.device))
                 ser.write(data)
+        finally:
+            self.serial_lock.release()
 
 
 # vim:sw=4:ts=4:et: