t7060: actually test "git diff-index --cached -M"
t7060: actually test "git diff-index --cached -M"

A test was designed for "git diff-index --cached -M" but the command is
run without the "-M" option (which makes the test essentially identical
to its preceding counterpart).

Signed-off-by: Matthieu Prat <5a54419687edbbb8a7de9e0b431b1f0134127fb6@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git