graft: do not use `.remove` on a smart set (regression)

Revset calls use to return a list. Graft use to mutate that list. We cannot do
this anymore leading to a crash when grafting multiple changeset with a revset.

    File ".../mercurial/commands.py", line 3117, in graft
      revs.remove(rev)
    AttributeError: '_addset' object has no attribute 'remove'

We are late in code-freeze so we make the shortest possible fix by turning it
back to a list.

mercurial/commands.py

@@ -3110,10 +3110,14 b' def graft(ui, repo, *revs, **opts):'
     # check for ancestors of dest branch
     crev = repo['.'].rev()
     ancestors = repo.changelog.ancestors([crev], inclusive=True)
+    # Cannot use x.remove(y) on smart set, this has to be a list.
+    # XXX make this lazy in the future
+    revs = list(revs)
     # don't mutate while iterating, create a copy
     for rev in list(revs):
         if rev in ancestors:
             ui.warn(_('skipping ancestor revision %s\n') % rev)
+            # XXX remove on list is slow
             revs.remove(rev)
     if not revs:
         return -1

tests/test-graft.t

@@ -571,3 +571,14 b' All copies of a cset'
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     2
   
+
+graft works on complex revset
+
+  $ hg graft 'origin(13) or destination(origin(13))'
+  skipping ancestor revision 21
+  skipping ancestor revision 22
+  skipping revision 2 (already grafted to 22)
+  grafting revision 7
+  grafting revision 13
+  grafting revision 19
+  merging b