[PATCH] Test case that demonstrates problem with --merge-order ^ processing

Added a test case that shows that --merge-order doesn't produce the
correct result in the following case.

A
|
| B
|/
C
|
D

git-rev-list --merge-order A ^B should produce just A. Instead
it produces BCD.

A subsequent patch will fix this defect.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

t/t6001-rev-list-merge-order.sh

@@ -543,6 +543,11 @@ test_output_expect_success 'simple merge order (r1l5)' 'git-rev-list --merge-ord
 = alt_root
 EOF
 
+test_output_expect_success "don't print things unreachable from one branch" "git-rev-list a3 ^b3 --merge-order" <<EOF
+a3
+a2
+a1
+EOF
 
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