configitems: register the 'server.uncompressedallowsecret' config

mercurial/configitems.py

@@ -134,6 +134,9 b" coreconfigitem('server', 'maxhttpheaderl"
 coreconfigitem('server', 'preferuncompressed',
     default=False,
 )
+coreconfigitem('server', 'uncompressedallowsecret',
+    default=False,
+)
 coreconfigitem('ui', 'clonebundleprefers',
     default=list,
 )

mercurial/streamclone.py

@@ -172,7 +172,7 b' def allowservergeneration(repo):'
     # So don't allow this by default.
     secret = phases.hassecret(repo)
     if secret:
-        return repo.ui.configbool('server', 'uncompressedallowsecret', False)
+        return repo.ui.configbool('server', 'uncompressedallowsecret')
 
     return True