Fix worker default web_host to be None

[ran-ka]

Description

This pull request only removes the default web_host value when starting the worker from the CLI. This way, if web_host is not provider in the CLI, the app will use the default web_host which is socket.gethostname() as set in settings.py

Not sure why this was kept this way, maybe it's something that was forgotten when moving the configuration to settings.py

Config order of precendence:

1. Worker CLI config (--web_host, --web_port)
2. Apps init config
3. Default config (settings.py)

[codecov-commenter]

Codecov Report

Merging #210 (2aca497) into master (9385c81) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #210   +/-   ##
=======================================
  Coverage   94.40%   94.40%           
=======================================
  Files         100      100           
  Lines       10740    10740           
  Branches     1214     1214           
=======================================
  Hits        10139    10139           
  Misses        536      536           
  Partials       65       65           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9385c81...2aca497. Read the comment docs.