Revert of Added virtualenv for depot_tools

Revert of Added virtualenv for depot_tools (patchset #10 id:180001 of https://chromiumcodereview.appspot.com/1200843003/)

Reason for revert:
Doesn't work, virtualenv is missing in depot_tools checkout.

Original issue's description:
> Added virtualenv for depot_tools
> 
> R=pgervais@chromium.org
> BUG=503067
> TEST=tested on Mac, Windows and Linux bots
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=295811

TBR=pgervais@chromium.org,sergiyb@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=503067
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=295813

[Adrian Kuegel, 2015-06-24 08:38:58]

Created Revert of Added virtualenv for depot_tools

[commit-bot: I haz the power, 2015-06-24 08:39:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1202843005/1

[commit-bot: I haz the power, 2015-06-24 08:39:17]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-24 08:39:18]

Failed to apply patch for update_depot_tools.bat:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file update_depot_tools.bat
  Hunk #1 FAILED at 26 (different line endings).
  1 out of 1 hunk FAILED -- saving rejects to file update_depot_tools.bat.rej

Patch:       update_depot_tools.bat
Index: update_depot_tools.bat
diff --git a/update_depot_tools.bat b/update_depot_tools.bat
index
43bdbabb7d675fe5942dd9834db2e8eaad8b314c..33fa40b220e8755ec693c924dc135e8a0e7be6c0
100644
--- a/update_depot_tools.bat
+++ b/update_depot_tools.bat
@@ -26,11 +26,6 @@
 if errorlevel 1 goto :EOF
 :: Now clear errorlevel so it can be set by other programs later.
 set errorlevel=
-
-:: Initialize/update virtualenv.
-cd "%DEPOT_TOOLS_DIR%"
-python -u bootstrap\bootstrap.py --deps_file bootstrap\deps.pyl ENV
-if errorlevel 1 goto :EOF
 
 :: Shall skip automatic update?
 IF "%DEPOT_TOOLS_UPDATE%" == "0" GOTO :EOF

[Adrian Kuegel, 2015-06-24 08:50:45]

Committed patchset #2 (id:210001) manually as 295813 (presubmit successful).

[pgervais, 2015-06-24 15:43:56]

On 2015/06/24 08:50:45, Adrian Kuegel wrote:
> Committed patchset #2 (id:210001) manually as 295813 (presubmit successful).

lgtm

https/crbug.com/503883 has been filed to requested adding virtualenv to
depot_tools. There might be duplicates of this ticket.