freebsd: made SerialLineReceiverBase's delimiter platform specific

utils.py

 from twisted.protocols.basic import LineReceiver
 import json
 import logging
+import platform
+
 
 logger = logging.getLogger()
+system = platform.system()
 
 
 class SerialLineReceiverBase(LineReceiver, object):
-    delimiter = '\n'
     MAX_LENGTH = 1024*1024*128
 
+    def __init__(self, *args, **kwargs):
+        if system == "FreeBSD":
+            self.delimiter = '\n'
+        else:
+            self.delimiter = '\r'
+        super(SerialLineReceiverBase, self).__init__(*args, **kwargs)
+
     def send_response(self, response, args):
         self.transport.write(json.dumps({'response': response,
                                          'args': args}) + '\r\n')