Don't ignore exceptions thrown in app_usage_monitor if given a bad request (one containing a None/nil value)

code/client/app_usage_monitor

@@ -48,7 +48,7 @@ except ImportError:
     sys.exit(-1)
 
 # our libs
-from munkilib.wrappers import writePlistToString
+from munkilib.wrappers import writePlistToString, PlistWriteError
 
 
 APPUSAGED_SOCKET = "/var/run/appusaged"
@@ -74,7 +74,11 @@ class AppUsageClient(object):
 
     def send_request(self, request):
         '''Send a request to appusaged'''
-        self.socket.send(writePlistToString(request))
+        try:
+            request_string = writePlistToString(request)
+            self.socket.send(request_string)
+        except PlistWriteError as err:
+            return "ERROR:Bad request: %s" % err
         # use select so we don't hang indefinitely if appusaged dies
         ready = select.select([self.socket.fileno()], [], [], 2)
         if ready[0]: