extensions: drop dead code trying to exclude deprecated disabled commands

Here 'ext' is a tuple, which means ext.__doc__ describes about the Python
tuple type. Fixing this would break 'hg help glog', which currently shows
some nice explanation, so this patch just removes the dead code.

  $ hg help glog
  'glog' is provided by the following extension:

      graphlog      command to view revision graphs from a shell (DEPRECATED)

  (use 'hg help extensions' for information on enabling extensions)

mercurial/extensions.py

@@ -696,7 +696,7 b' def disabledcmd(ui, cmd, strict=False):'
             ext = findcmd(cmd, name, path)
             if ext:
                 break
-    if ext and 'DEPRECATED' not in ext.__doc__:
+    if ext:
         return ext
 
     raise error.UnknownCommand(cmd)