update: just merge unknown file collisions

update: just merge unknown file collisions

The unknown file collision rule was introduced as an extension of the
"should be clean when merging" rule. Unfortunately, it got applied to
the normal update path, which should be happy to merge local changes.

This patch gives us merges for unknown file collisions on update,
while preserving abort for merge and update -c.

--- a/mercurial/commands.py	Thu Feb 09 17:04:17 2012 -0600
+++ b/mercurial/commands.py	Thu Feb 09 17:54:47 2012 -0600
@@ -5723,6 +5723,7 @@
             raise util.Abort(_("uncommitted local changes"))
         if not rev:
             rev = repo[repo[None].branch()].rev()
+        mergemod._checkunknown(repo, repo[None], repo[rev])
 
     if clean:
         ret = hg.clean(repo, rev)

--- a/mercurial/merge.py	Thu Feb 09 17:04:17 2012 -0600
+++ b/mercurial/merge.py	Thu Feb 09 17:54:47 2012 -0600
@@ -545,6 +545,8 @@
             if not force and (wc.files() or wc.deleted()):
                 raise util.Abort(_("outstanding uncommitted changes"),
                                  hint=_("use 'hg status' to list changes"))
+            if not force:
+                _checkunknown(repo, wc, p2)
             for s in wc.substate:
                 if wc.sub(s).dirty():
                     raise util.Abort(_("outstanding uncommitted changes in "
@@ -566,8 +568,6 @@
         ### calculate phase
         action = []
         folding = not util.checkcase(repo.path)
-        if not force:
-            _checkunknown(repo, wc, p2)
         if folding:
             _checkcollision(p2, branchmerge and p1)
         action += _forgetremoved(wc, p2, branchmerge)