match: remove a mutable default argument

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

mercurial/scmutil.py

@@ -778,7 +778,7 b' def matchandpats(ctx, pats=(), opts=None'
         pats = []
     return m, pats
 
-def match(ctx, pats=[], opts={}, globbed=False, default='relpath', badfn=None):
+def match(ctx, pats=(), opts={}, globbed=False, default='relpath', badfn=None):
     '''Return a matcher that will warn about bad matches.'''
     return matchandpats(ctx, pats, opts, globbed, default, badfn=badfn)[0]