t2407: fix broken &&-chains in compound statement

t2407: fix broken &&-chains in compound statement

The breaks in the &&-chain in this test went unnoticed because the
"magic exit code 117" &&-chain checker built into test-lib.sh only
recognizes broken &&-chains at the top-level; it does not work within
`{...}` groups, `(...)` subshells, `$(...)` substitutions, or within
bodies of compound statements, such as `if`, `for`, `while`, `case`,
etc. Furthermore, `chainlint.sed` detects broken &&-chains only in
`(...)` subshells. Thus, the &&-chain breaks in this test fall into the
blind spots of the &&-chain linters.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>