configitems: register the 'convert.hg.usebranchnames' config

hgext/convert/__init__.py

@@ -88,6 +88,9 b" configitem('convert', 'hg.startrev',"
 configitem('convert', 'hg.tagsbranch',
     default='default',
 )
+configitem('convert', 'hg.usebranchnames',
+    default=True,
+)
 
 # Commands definition was moved elsewhere to ease demandload job.
 

hgext/convert/hg.py

@@ -47,7 +47,7 b" sha1re = re.compile(r'\\b[0-9a-f]{12,40}\\"
 class mercurial_sink(common.converter_sink):
     def __init__(self, ui, path):
         common.converter_sink.__init__(self, ui, path)
-        self.branchnames = ui.configbool('convert', 'hg.usebranchnames', True)
+        self.branchnames = ui.configbool('convert', 'hg.usebranchnames')
         self.clonebranches = ui.configbool('convert', 'hg.clonebranches')
         self.tagsbranch = ui.config('convert', 'hg.tagsbranch')
         self.lastbranch = None