t4014: support Git version strings with spaces

t4014: support Git version strings with spaces

git --version reports its version with the prefix "git version ".
Remove precisely this string instead of everything up to and including
the rightmost space to avoid butchering version strings that contain
spaces.  This helps Apple's release of Git, which reports its version
like this: "git version 2.50.1 (Apple Git-155)".

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>