commit: move salvaged calculation a bit earlier in the function

This helps us initialize mergestate before and now we can pass it into
`_process_files()` instead of re-reading it there.

Differential Revision: https://phab.mercurial-scm.org/D9192

mercurial/commit.py

@@ -114,6 +114,8 b' def _prepare_files(tr, ctx, error=False,'
     p1 = ctx.p1()
 
     writechangesetcopy, writefilecopymeta = _write_copy_meta(repo)
+    ms = mergestate.mergestate.read(repo)
+    salvaged = _get_salvaged(repo, ms, ctx)
 
     if ctx.manifestnode():
         # reuse an existing manifest revision
@@ -140,8 +142,6 b' def _prepare_files(tr, ctx, error=False,'
         files.update_copies_from_p1(ctx.p1copies())
         files.update_copies_from_p2(ctx.p2copies())
 
-    ms = mergestate.mergestate.read(repo)
-    salvaged = _get_salvaged(ctx.repo(), ms, ctx)
     for s in salvaged:
         files.mark_salvaged(s)