merge-one-file: remove stale comment

The "funny filename" comment was from b539c5e (git-merge-one:
new merge world order., 2005-12-07) where the removed code just
before that new comment ended with:

        merge "$4" "$orig" "$src2"

(yes, we used to use "merge" program from the RCS suite).  The
comment refers to one of the bad side effect the old code used to
have and warns against such a practice, i.e. it was talking about
the code that no longer existed.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-merge-one-file.sh

@@ -118,8 +118,6 @@ case "${1:-.}${2:-.}${3:-.}" in
 		;;
 	esac
 
-	# Be careful for funny filename such as "-L" in "$4", which
-	# would confuse "merge" greatly.
 	git merge-file "$src1" "$orig" "$src2"
 	ret=$?
 	msg=