Revert of Add extensions parameter to Pylint presubmit check. (patchset #1 id:1 of https://codereview.chromium.org/1639493003/ )

Reason for revert:
Sorry, turns out this change isn't necessary. You can specify extension-pkg-whitelist in pylintrc.

Original issue's description:
> Add extensions parameter to Pylint presubmit check.
> 
> This allows Pylint to analyze code that relies on C extensions (like numpy).
> https://bitbucket.org/logilab/pylint/issues/58#comment-14920640
> 
> 
> BUG=
> 
> Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=298392

TBR=dpranke@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=

Review URL: https://codereview.chromium.org/1646633002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@298419 0039d316-1c4b-4281-b951-d872f2087c98