t/lib-gpg: require GPGSSH for GPGSSH_VERIFYTIME prereq
The GPGSSH_VERIFYTIME prequeq makes use of "${GNUPGHOME}" but does not
create it. Require GPGSSH which creates the "${GNUPGHOME}" directory.
Additionally, it makes sense to require GPGSSH in GPGSSH_VERIFYTIME
because the latter builds on the former. If we can't use GPGSSH,
there's little point in checking whether GPGSSH_VERIFYTIME is usable.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>