Add RegisterFallbackResource to /_matrix/static/client/register

Try to keep both forms of registration logic (native/fallback) close
together for sanity.

synapse/rest/client/v1/register.py

@@ -18,10 +18,12 @@ from twisted.internet import defer
 
 from synapse.api.errors import SynapseError, Codes
 from synapse.api.constants import LoginType
+from synapse.api.urls import STATIC_PREFIX
 from base import ClientV1RestServlet, client_path_pattern
 import synapse.util.stringutils as stringutils
 
 from synapse.util.async import run_on_reactor
+from twisted.web.resource import Resource
 
 from hashlib import sha1
 import hmac
@@ -305,6 +307,16 @@ class RegisterRestServlet(ClientV1RestServlet):
         })
 
 
+class RegisterFallbackResource(Resource):
+
+    def __init__(self, hs):
+        Resource.__init__(self)  # Resource is an old-style class :(
+        self.hs = hs
+
+    def render_GET(self, request):
+        return "NOT_YET_IMPLEMENTED"
+
+
 def _parse_json(request):
     try:
         content = json.loads(request.content.read())
@@ -315,5 +327,14 @@ def _parse_json(request):
         raise SynapseError(400, "Content not JSON.")
 
 
+def get_prefixes_and_resources(hs):
+    return [
+        (
+            STATIC_PREFIX + "/client/register",
+            RegisterFallbackResource(hs)
+        )
+    ]
+
+
 def register_servlets(hs, http_server):
     RegisterRestServlet(hs).register(http_server)