Remove WORKSPACE to ensure we can clone infra/test repo

Change-Id: I36c4a62608bd22fcda34be31b1a1a9eb8272249f
diff --git a/jjb/cloud-infra/prepare-for-test.sh b/jjb/cloud-infra/prepare-for-test.sh
index 4e60a8a..7b9104b 100644
--- a/jjb/cloud-infra/prepare-for-test.sh
+++ b/jjb/cloud-infra/prepare-for-test.sh
@@ -22,7 +22,7 @@
 set -o nounset
 
 echo "Info: Cloning infra/test repository"
-/bin/rm -rf $WORKSPACE/*
+/bin/rm -rf $WORKSPACE
 git clone -q $TEST_REPO_URL $WORKSPACE
 
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