1.6.1dev: adapt to Subversion 1.14.5 which svn.fs.closest_copy retu…

…rns `(None, None)` when no given copy exists instead `None` (closes #13867)

git-svn-id: http://trac.edgewall.org/intertrac/log:/branches/1.6-stable@17883 af82e41b-90c4-0310-8c96-b1721e28e2e2

tracopt/versioncontrol/svn/svn_fs.py

@@ -834,9 +834,10 @@ def get_branch_origin(self):
 
         (wraps ``fs.revision_root_revision(fs.closest_copy)``)
         """
-        root_and_path = fs.closest_copy(self.root, self._scoped_path_utf8)
-        if root_and_path:
-            return fs.revision_root_revision(root_and_path[0])
+        root, path = fs.closest_copy(self.root, self._scoped_path_utf8) or \
+                     (None, None)
+        if root is not None:
+            return fs.revision_root_revision(root)
 
     def get_copy_ancestry(self):
         """Retrieve the list of `(path,rev)` copy ancestors of this node.
@@ -849,9 +850,9 @@ def get_copy_ancestry(self):
         while previous:
             (previous_path, previous_rev, previous_root) = previous
             previous = None
-            root_path = fs.closest_copy(previous_root, previous_path)
-            if root_path:
-                (root, path) = root_path
+            root, path = fs.closest_copy(previous_root, previous_path) or \
+                         (None, None)
+            if root is not None:
                 path = path.lstrip(b'/')
                 rev = fs.revision_root_revision(root)
                 relpath = None