re-introduce old nss im too tired for this

security/nss/automation/taskcluster/docker-hacl/bin/checkout.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+set -v -e -x
+
+if [ $(id -u) = 0 ]; then
+    # Drop privileges by re-running this script.
+    exec su worker $0
+fi
+
+# Default values for testing.
+REVISION=${NSS_HEAD_REVISION:-default}
+REPOSITORY=${NSS_HEAD_REPOSITORY:-https://hg.mozilla.org/projects/nss}
+
+# Clone NSS.
+for i in 0 2 5; do
+    sleep $i
+    hg clone -r $REVISION $REPOSITORY nss && exit 0
+    rm -rf nss
+done
+exit 1