Add liberasurecode-dev as a swift dependency

Swift requirement PyECLib won't bundle liberasurecode
going forward given the package is available in common
distros now.  This patch adds liberasurecode-dev(el)
package to the devstack debs/rpms list for Swift as a
PyECLib build/install dependency.

Change-Id: Idbc2ca3f677f1b8153ebf3a5912f4354525a55c7
diff --git a/files/debs/swift b/files/debs/swift
index 726786e..4b8ac3d 100644
--- a/files/debs/swift
+++ b/files/debs/swift
@@ -1,4 +1,5 @@
 curl
+liberasurecode-dev
 make
 memcached
 sqlite3