Add swift tempurl support to devstack

This commit adds the ability to automatically set a tempurl key
in swift for service accounts.

Change-Id: I0d5d16c5601d022f034df2cc291106c5dc13511e
diff --git a/stack.sh b/stack.sh
index 03ecf28..3e8f7e9 100755
--- a/stack.sh
+++ b/stack.sh
@@ -472,6 +472,10 @@
     # ``SWIFT_HASH`` is a random unique string for a swift cluster that
     # can never change.
     read_password SWIFT_HASH "ENTER A RANDOM SWIFT HASH."
+
+    if [[ -z "$SWIFT_TEMPURL_KEY" ]] && [[ "$SWIFT_ENABLE_TEMPURLS" == "True" ]]; then
+        read_password SWIFT_TEMPURL_KEY "ENTER A KEY FOR SWIFT TEMPURLS."
+    fi
 fi