read-tree --aggressive

A new flag --aggressive resolves what we traditionally resolved
with external git-merge-one-file inside index while read-tree
3-way merge works.

git-merge-octopus and git-merge-resolve use this flag before
running git-merge-index with git-merge-one-file.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/git-merge-resolve.sh b/git-merge-resolve.sh
index 966e81f..0a8ef21 100755
--- a/git-merge-resolve.sh
+++ b/git-merge-resolve.sh
@@ -38,7 +38,7 @@
 fi
 
 git-update-index --refresh 2>/dev/null
-git-read-tree -u -m $bases $head $remotes || exit 2
+git-read-tree -u -m --aggressive $bases $head $remotes || exit 2
 echo "Trying simple merge."
 if result_tree=$(git-write-tree  2>/dev/null)
 then