configitems: rename the config to prevent adding an alias in future stable

configitems: rename the config to prevent adding an alias in future

Right now the config option looks like:

[experimental.server]
stream-narrow-clones=

which does not match how config options are generally defined in core. So let's
rename this to:

[experimental]
server.stream-narrow-clones=

before the new release so that we don't have to add an alias in future for this.

Differential Revision: https://phab.mercurial-scm.org/D5198

--- a/mercurial/bundle2.py	Wed Oct 31 11:02:08 2018 +0100
+++ b/mercurial/bundle2.py	Wed Oct 31 15:27:06 2018 +0300
@@ -1691,8 +1691,8 @@
     includepats = kwargs.get(r'includepats')
     excludepats = kwargs.get(r'excludepats')
 
-    narrowstream = repo.ui.configbool('experimental.server',
-                                      'stream-narrow-clones')
+    narrowstream = repo.ui.configbool('experimental',
+                                      'server.stream-narrow-clones')
 
     if (includepats or excludepats) and not narrowstream:
         raise error.Abort(_('server does not support narrow stream clones'))

--- a/mercurial/configitems.py	Wed Oct 31 11:02:08 2018 +0100
+++ b/mercurial/configitems.py	Wed Oct 31 15:27:06 2018 +0300
@@ -610,7 +610,7 @@
 coreconfigitem('experimental', 'server.manifestdata.recommended-batch-size',
     default=100000,
 )
-coreconfigitem('experimental.server', 'stream-narrow-clones',
+coreconfigitem('experimental', 'server.stream-narrow-clones',
     default=False,
 )
 coreconfigitem('experimental', 'single-head-per-branch',