clonebundles: move the manifest reading in a dedicated function

We are about to make the logic more advanced to help hosting solution, so we
need to centralize it first.

mercurial/bundlecaches.py

@@ -25,6 +25,9 b' urlreq = util.urlreq'
 
 CB_MANIFEST_FILE = b'clonebundles.manifest'
 
+def get_manifest(repo):
+    return repo.vfs.tryread(CB_MANIFEST_FILE)
+
 
 @attr.s
 class bundlespec:

mercurial/localrepo.py

@@ -349,7 +349,7 b' class localpeer(repository.peer):'
         return self._caps
 
     def clonebundles(self):
-        return self._repo.tryread(bundlecaches.CB_MANIFEST_FILE)
+        return bundlecaches.get_manifest(self._repo)
 
     def debugwireargs(self, one, two, three=None, four=None, five=None):
         """Used to test argument passing over the wire"""

mercurial/wireprotov1server.py

@@ -274,9 +274,8 b' def clonebundles(repo, proto):'
     depending on the request. e.g. you could advertise URLs for the closest
     data center given the client's IP address.
     """
-    return wireprototypes.bytesresponse(
-        repo.vfs.tryread(bundlecaches.CB_MANIFEST_FILE)
-    )
+    manifest = bundlecaches.get_manifest(repo)
+    return wireprototypes.bytesresponse(manifest)
 
 
 wireprotocaps = [