t7201: drop pointless "exit 0" at end of subshell

This test employs a for-loop inside a subshell and correctly aborts the loop and fails the test overall (via "exit 1") if any iteration of the for-loop fails. Otherwise, it exits the subshell with an explicit but entirely unnecessary "exit 0", presumably to indicate that all iterations of the loop succeeded. The &&-chain is broken between the for-loop and the "exit 0". Rather than fixing the &&-chain, just drop the pointless "exit 0". Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>