docker: docker.py wrap StringIO import for python3

Although the docker.py is nominally python2 we actually invoke it with
the configured python from the configure script.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

diff --git a/tests/docker/docker.py b/tests/docker/docker.py
index 306e14cf69440ec5ae3f6d808548936c603decec..e4095270eb10b0a80fd560291da7cbdfd110a592 100755 (executable)
--- a/tests/docker/docker.py
+++ b/tests/docker/docker.py
@@ -26,7 +26,10 @@ import tempfile
 import re
 import signal
 from tarfile import TarFile, TarInfo
-from StringIO import StringIO
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import StringIO
 from shutil import copy, rmtree
 from pwd import getpwuid