Follow up to crrev.com/c/2125626.

This allows depot_tools commands to run successfully when depot_tools is
installed in a path containing spaces.

Change-Id: I8f99dbdcb3b1acf27d51ce26b6153f643b8d4dcd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2127675
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Josip Sokcevic <sokcevic@google.com>

Retrying the change in https://codereview.chromium.org/1415993003/, with
fixes to properly handle being called with either Windows- or
POSIX-style paths (the previous attempt assumed it was always called
with POSIX-style paths under MSYS, which itself was attempting to fix
the assumption that it was always called with Windows-style paths, but
neither assumption was right).

This change doesn't actually use the wrapper in any new places, but
subsequent changes will be made to use it in places where
'exec python' is called directly, like gclient and fetch.

BUG=411518
R=iannucci@google.com, sky@google.com

Review URL: https://codereview.chromium.org/1411793006

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@297401 0039d316-1c4b-4281-b951-d872f2087c98

Revert of Generalize python_git_runner for use in non-git scripts. (patchset #1 id:1 of https://codereview.chromium.org/1415993003/ )

Reason for revert:
Speculative revert in case this caused the bots to fail bot_update.

Original issue's description:
> Generalize python_git_runner for use in non-git scripts.
> 
> Also fixes an msys (git-bash) incompatibility, similar to the one
> fixed in crrev.com/4845f0ed.
> 
> This change doesn't actually use the wrapper in any new places, but
> subsequent changes will be made to use it in places where
> 'exec python' is called directly, like gclient and fetch.
> 
> BUG=411518
> R=iannucci@google.com
> 
> Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=297357

TBR=iannucci@google.com,iannucci@chromium.org,mmoss@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=411518

Review URL: https://codereview.chromium.org/1414923008

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@297358 0039d316-1c4b-4281-b951-d872f2087c98

Also fixes an msys (git-bash) incompatibility, similar to the one
fixed in crrev.com/4845f0ed.

This change doesn't actually use the wrapper in any new places, but
subsequent changes will be made to use it in places where
'exec python' is called directly, like gclient and fetch.

BUG=411518
R=iannucci@google.com

Review URL: https://codereview.chromium.org/1415993003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@297357 0039d316-1c4b-4281-b951-d872f2087c98

Invoke the bash shell via /usr/bin/env so that these scripts run on operating systems without /bin/bash too.

TEST=run "git cl owners" on FreeBSD
BUG=

Review URL: https://codereview.chromium.org/197213008

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@274320 0039d316-1c4b-4281-b951-d872f2087c98

R=agable@chromium.org, hinoka@chromium.org, stip@chromium.org, szager@chromium.org
BUG=261738

Review URL: https://codereview.chromium.org/181043018

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@256778 0039d316-1c4b-4281-b951-d872f2087c98