tests/test-rename-merge1.out

merge: do early copy to deal with issue636

Without copies/renames, merges source names are 1:1 with their
targets. Copies and renames introduce the possibility that there will
be two merges with the same input but different output. By doing the
copy to the destination name before the merge, the actual merge
becomes 1:1 again, and no source is the input to two different merges.

- add a preliminary scan to applyupdates to do copies
- for the merge action, pass the old name (for finding ancestors) and
  the new name (for input to the merge) to filemerge
- eliminate the old post-merge copy
- lookup file contents from new name in filemerge
- pass new name to external merge helper
- report merge failure at new name
- add a test

checkout
2 files updated, 0 files merged, 2 files removed, 0 files unresolved
merge
resolving manifests
 overwrite None partial False
 ancestor af1939970a1c local f26ec4fc3fa3+ remote 8e765a822af2
 a2: divergent renames -> dr
 a: remote moved to b -> m
 b2: remote created -> g
copying a to b
merging a and b
my a@f26ec4fc3fa3+ other b@8e765a822af2 ancestor a@af1939970a1c
removing a
warning: detected divergent renames of a2 to:
 c2
 b2
getting b2
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
M b
  a
M b2
R a
C c2
blahblah
   rev    offset  length   base linkrev nodeid       p1           p2
     0         0      67      0       1 dc51707dfc98 000000000000 000000000000
     1        67      72      1       3 b2494a44f0a9 000000000000 dc51707dfc98
b renamed from a:dd03b83622e78778b403775d0d074b9ac7387a66