blackbox: remove hexfn

It was introduced as copy+paste code, but was never necessary.

hgext/blackbox.py

@@ -71,12 +71,6 b' def _closelog(vfs):'
     del filehandles[path]
     fp.close()
 
-def hexfn(node):
-    if node is None:
-        return None
-    else:
-        return hex(node)
-
 def wrapui(ui):
     class blackboxui(ui.__class__):
         def __init__(self, src=None):
@@ -173,11 +167,8 b' def wrapui(ui):'
                 changed = ''
                 if ui._bbrepo:
                     ctx = ui._bbrepo[None]
-                    if ctx.rev() is not None:
-                        rev = hexfn(ctx.node())
-                    else:
                         parents = ctx.parents()
-                        rev = ('+'.join([hexfn(p.node()) for p in parents]))
+                    rev = ('+'.join([hex(p.node()) for p in parents]))
                         if (ui.configbool('blackbox', 'dirty', False) and (
                             any(ui._bbrepo.status()) or
                             any(ctx.sub(s).dirty() for s in ctx.substate)