[PATCH] Need to set PAGER in tests

"t5400-send-pack.sh --verbose" stops waiting for user input.  It happens
because "git log" uses less for output now.  To prevent this, PAGER
should be set to cat.

Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>