Serve keys from canonical project name

Rather than asking users to know the 'source' name in order to
retrieve the project's public key, use the tenant and canonical
project name.  The tenant already appears in most web urls, and
the project name should be known to the user.

Change-Id: Icd1269ffdd8879bd177fd452978a2c88b2f1b205
diff --git a/tools/encrypt_secret.py b/tools/encrypt_secret.py
index 9b52846..2a4ea1d 100755
--- a/tools/encrypt_secret.py
+++ b/tools/encrypt_secret.py
@@ -43,10 +43,7 @@
     parser.add_argument('url',
                         help="The base URL of the zuul server and tenant.  "
                         "E.g., https://zuul.example.com/tenant-name")
-    # TODO(jeblair,mordred): When projects have canonical names, use that here.
     # TODO(jeblair): Throw a fit if SSL is not used.
-    parser.add_argument('source',
-                        help="The Zuul source of the project.")
     parser.add_argument('project',
                         help="The name of the project.")
     parser.add_argument('--infile',
@@ -61,8 +58,7 @@
                         "to standard output.")
     args = parser.parse_args()
 
-    req = Request("%s/keys/%s/%s.pub" % (
-        args.url, args.source, args.project))
+    req = Request("%s/%s.pub" % (args.url, args.project))
     pubkey = urlopen(req)
 
     if args.infile: