t7401: modernize style

t7401: modernize style

The tests in 't7401-submodule-summary.sh' were written a long time ago
and has a violation with respect to our CodingGuidelines which is,
incorrect spacing in usages of the redirection operator.

Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Helped-by: Denton Liu <liu.denton@gmail.com>
Helped-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Shourya Shukla <shouryashukla.oo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>