t/lib-gpg: reload gpg components after updating trustlist

With gpgsm from gnupg-2.3, the changes to the trustlist.txt do not
appear to be picked up without refreshing the gpg-agent.  Use the 'all'
keyword to reload all of the gpg components.  The scdaemon is started as
a child of gpg-agent, for example.

We used to have a --kill at this spot, but I removed it in 2e285e7803
(t/lib-gpg: drop redundant killing of gpg-agent, 2019-02-07).  It seems
like it might be necessary (again) for 2.3.

Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-gpg.sh

@@ -75,6 +75,7 @@ test_lazy_prereq GPGSM '
 	gpgsm --homedir "${GNUPGHOME}" -K --with-colons |
 	awk -F ":" "/^fpr:/ {printf \"%s S relax\\n\", \$10}" \
 		>"${GNUPGHOME}/trustlist.txt" &&
+	(gpgconf --reload all || : ) &&
 
 	echo hello | gpgsm --homedir "${GNUPGHOME}" >/dev/null \
 	       -u committer@example.com -o /dev/null --sign -