text: Title: Daemon stops running
  Body: ## Mycodo Issue Report:
    - Specific Mycodo Version: 6.1.4
   
  #### Problem Description
  Daemon stops running. It ran for a couple days, then stopped after a restart. Seems to have something to do with usage report. I have my only output set at 8A. Max amps, under configuration, is 15A. I have it run usage once a month, this is all that I've configured differently in the last week.
   
  ### Errors
  This is similar to the issues I had earlier this week. This is a clean install, on a new flash disk. I set everything up again. Restarted and the Daemon shows not running. 
  
  ### Steps to Reproduce the issue:
  How can this issue be reproduced?
  It seems that 6.1.4 is unstable with regards to output usage statistics. Earlier versions had no issues and ran for over a month without a problem. Once I set 0A on my output, and disable running usage reports, I restart the daemon and it seems to run.
   
  ### Additional Notes
  I see this under Daemon logs:
  2018-07-15 21:51:58,245 - mycodo.daemon - INFO - All Conditional controllers stopped
  2018-07-15 21:51:58,245 - mycodo.daemon - INFO - All LCD controllers stopped
  2018-07-15 21:51:58,253 - mycodo.input_df812159 - INFO - Deactivated in 8.6 ms
  2018-07-15 21:51:58,263 - mycodo.input_1b9b8ca5 - INFO - Deactivated in 17.9 ms
  2018-07-15 21:51:58,274 - mycodo.input_874ae506 - INFO - Deactivated in 28.6 ms
  2018-07-15 21:52:05,093 - mycodo.pid_12b78e75 - WARNING - No data returned from influxdb
  2018-07-15 21:52:05,431 - mycodo.pid_12b78e75 - INFO - Deactivated in 7186.2 ms
  2018-07-15 21:52:05,432 - mycodo.daemon - INFO - All PID controllers stopped
  2018-07-15 21:52:05,433 - mycodo.daemon - INFO - All Math controllers stopped
  2018-07-15 21:52:05,434 - mycodo.daemon - INFO - All Input controllers stopped
  2018-07-15 21:52:05,495 - mycodo.daemon - ERROR - ERROR Starting Mycodo Daemon
  Traceback (most recent call last):
    File "/var/mycodo-root/mycodo/mycodo_daemon.py", line 1080, in start_daemon
      self.mycodo.run()
    File "/var/mycodo-root/mycodo/mycodo_daemon.py", line 399, in run
      now > self.output_usage_report_next_gen):
  TypeError: unorderable types: float() > NoneType()