Add pylint hook to crostestutils to make sure crostestutils passes pylint.

BUG=chromium-os:11550
TEST=Verify presubmit hook catches when there are pylint errors.

Change-Id: Ia20775756020d4eabcec762509795b0fe6b3da6c
Reviewed-on: https://gerrit.chromium.org/gerrit/39754
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Ready: David James <davidjames@chromium.org>
Tested-by: David James <davidjames@chromium.org>
diff --git a/PRESUBMIT.cfg b/PRESUBMIT.cfg
new file mode 100644
index 0000000..2cdbcc6
--- /dev/null
+++ b/PRESUBMIT.cfg
@@ -0,0 +1,2 @@
+[Hook Scripts]
+hook0=../../../chromite/bin/cros lint ${PRESUBMIT_FILES}