Delete all .pyc on update. Stale .pyc can cause weird issues.
Delete all .pyc on update. Stale .pyc can cause weird issues.

Take two at r102841.

Forgot to use $base_dir, so the .pyc files in the checkout were deleted, instead
of the ones in depot_tools. Since some slaves have very large checkouts, they
appeared as hung.

R=cmp@chromium.org
BUG=
TEST=


Review URL: http://codereview.chromium.org/8059001

git-svn-id: bd64dd6fa6f3f0ed0c0666d1018379882b742947@103056 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

svn2github/chromium-depot-tools,svn2github/chromium-depot-tools,svn2github/chromium-depot-tools