Python 3/urllib: imports, timeout

[josephsl]

Link to issue number:

Fixes #9818

Summary of the issue:

Update check functionality does not work due to incomplete imports.

Description of how this pull request fixes the issue:

Edited update check module:

1. Import urllib.parse and urllib.request with an explanatory comment.
2. urllib.urlopen -> urllib.request.urlopen
3. urlib.urlencode -> urllib.parse.urlencode
4. For timeout, urlopen function is now used to specify timeout, thus moved the code and comments for Updating without administrative privileges fails with some antivirus apps running in background #2352 around.
5. Removed fp.soc line for specifying timeout, as urlopen now takes care of it.

Testing performed:

Tested with a custom build of Python 3 staging branch (with update version type specified) to simulate update check and via Python 3 interepreter.

Known issues with pull request:

More to be uncovered as update check module is converted.

Change log entry:

None