Revert of Adds bot_update to depot_tools. (patchset #8 id:140001 of https://codereview.chromium.org/1641363002/ )

Reason for revert:
Exposed recipe engine bug with ambiguous names, causing roller blockage.

Original issue's description:
> Adds bot_update to depot_tools.
> 
> This CL imports the bot_update script, along with the bot_update and gclient recipe modules from build. This should allow for recipes to run on swarming.
> 
> Also moves the recipe stuff into the infra folder.
> 
> bot_update has been modified. See full diff at https://paste.googleplex.com/4969207737352192
> 
> TBR=phajdan.jr@chromium.org
> 
> BUG=
> 
> Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=298490

TBR=iannucci@chromium.org,phajdan.jr@chromium.org,martiniss@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=

Review URL: https://codereview.chromium.org/1651323002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@298505 0039d316-1c4b-4281-b951-d872f2087c98