Add the missing 'import stat' line.
Accidentally broken by the cherry-pick in commit
f829b40c489781aba8fcd2aeb8c7900f7406e695 - the original CL in oc-dev
doesn't require the 'import stat' line.
Bug: 63629728
Test: `pylint --rcfile=pylintrc sign_target_files_apks.py`
Test: Successfully sign a build with sign_target_files_apks.py.
Change-Id: I94be613fb2219597148c4339ac33fc93d0cdae47
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 3cf8ce7..e671cd5 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -102,6 +102,7 @@
import errno
import os
import re
+import stat
import subprocess
import tempfile
import zipfile
