Revert "cbuildbot: Preserve chromite-bootstrap directory during Cleanup."

This reverts commit 47eaa5ebb6be1d866654f4e6f769c7ee1c3fa583.

The CL that introduced that dir path on the builders was reverted by
CL:272284. Because we have this exception to the Cleanup step, the
chromite-bootstrap directory is not getting cleaned up from the
builders.

This directory is no longer part of the build after CL:272284, so it
also makes sense to revert this CL, that was trying to preserve that
path.

BUG=chromium:489870
TEST=Launch a trybot on a slave that has the obsolete path, verify that
     the path disappears, and that the buildslave remains healthy
     afterwards.

Change-Id: I6b599232b9a80f3f56d0b3cf2fe88b951887c44d
Reviewed-on: https://chromium-review.googlesource.com/274532
Tested-by: Prathmesh Prabhu <pprabhu@chromium.org>
Trybot-Ready: Prathmesh Prabhu <pprabhu@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Commit-Queue: Prathmesh Prabhu <pprabhu@chromium.org>
diff --git a/scripts/cbuildbot.py b/scripts/cbuildbot.py
index cd823b5..46c6c40 100644
--- a/scripts/cbuildbot.py
+++ b/scripts/cbuildbot.py
@@ -1155,8 +1155,7 @@
     # https://chromium-review.googlesource.com/25359
     # is landed- it's sensitive to the manifest-versions cache path.
     options.preserve_paths = set(['manifest-versions', '.cache',
-                                  'manifest-versions-internal',
-                                  'chromite-bootstrap'])
+                                  'manifest-versions-internal'])
     if log_file is not None:
       # We don't want the critical section to try to clean up the tee process,
       # so we run Tee (forked off) outside of it. This prevents a deadlock