addremove: remove a mutable default argument

Mutable default arguments are know to the state of California to cause bugs.

mercurial/cmdutil.py

@@ -2763,7 +2763,9 b' def buildcommittext(repo, ctx, subs, ext'
 
     return "\n".join(edittext)
 
-def commitstatus(repo, node, branch, bheads=None, opts={}):
+def commitstatus(repo, node, branch, bheads=None, opts=None):
+    if opts is None:
+        opts = {}
     ctx = repo[node]
     parents = ctx.parents()