tests: rename duplicate t1009

We should avoid duplicate test numbers, since things like
GIT_SKIP_TESTS consider something like t1009.5 to be
unambiguous.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t1009-read-tree-sparse-checkout.sh b/t/t1011-read-tree-sparse-checkout.sh
similarity index 100%
rename from t/t1009-read-tree-sparse-checkout.sh
rename to t/t1011-read-tree-sparse-checkout.sh