Fix client.dynamorio recipe bugs

1) Fix the got_revision bug that's causing builds to fail
2) Remove the now-redundant 'clear tools directory' step (it's causing the Windows bots to fail), and change the recipe converter to reflect this
3) Change the directory into which the buildbot tools are checked out.

BUG=480029
R=iannucci,dnj

Review URL: https://codereview.chromium.org/1684443003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/build@298698 0039d316-1c4b-4281-b951-d872f2087c98
9 files changed