Add protection against environment variables overriding web proxy server

[nataliaratnikova]

Environment variables may override proxy server.
The site reported the following error during upload with spacecount command:

Error from server 500(Can't connect to cmsweb.cern.ch:443 (Bad service
'8080/')), output below:
500 Can't connect to cmsweb.cern.ch:443 (Bad service '8080/')

Work around was to unset all [HTTP|HTTPS|SSL]_PROXY variables .

See, if we can add protection on the application side.