Add swift support.

Based on github.sh/cloudbuilders/deploy.sh/swift. This is a WIP branch.
diff --git a/files/swift.conf b/files/swift.conf
new file mode 100644
index 0000000..98df466
--- /dev/null
+++ b/files/swift.conf
@@ -0,0 +1,3 @@
+[swift-hash]
+# random unique string that can never change (DO NOT LOSE)
+swift_hash_path_suffix = %SWIFT_HASH%