rev-list-options.txt: correct TREESAME for P
rev-list-options.txt: correct TREESAME for P

In the example given, P is not TREESAME to E. This doesn't affect the
current result, but it will matter when we change behaviour.

Signed-off-by: Kevin Bracey <ffb4761cba839470133bee36aeb139f58d7dbaa9@bracey.fi>
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