python_cleaner: ignore python-exec in version check

The new python-exec package installs dirs that get caught up in our
version checking logic.  Filter that out.

BUG=chromium:220911
TEST=`./update_chroot` no longer runs python_cleaner

Change-Id: I6fa6539cb8d1a3c98933c6f0939b861a59e616a5
Reviewed-on: https://chromium-review.googlesource.com/180111
Reviewed-by: Gaurav Shah <gauravsh@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/python_cleaner b/python_cleaner
index c31eb34..2a84ee6 100755
--- a/python_cleaner
+++ b/python_cleaner
@@ -51,7 +51,10 @@
 fi
 
 # If the user still has old python modules installed, update them.
-PYTHON_VERSIONS=( $(ls -d /usr/lib*/python*/ | cut -d/ -f4 | sort -uV) )
+PYTHON_VERSIONS=(
+  # Filter out the new python-exec package.
+  $(ls -d /usr/lib*/python*/ | cut -d/ -f4 | grep -v python-exec | sort -uV)
+)
 if [[ ${#PYTHON_VERSIONS[@]} -gt 1 ]]; then
   PY_UPDATE_FLAGS=()
   if [[ ${FLAGS_jobs} -ne -1 ]]; then