Add openssh-clients BuildRequires, for ssh-add. Upstream 350a2518c8
(ssh signing: support non ssh-* keytypes, 2021-11-19), added `ssh-add`
as a requirement of t7528-signed-commit-ssh's "sign commits using
literal public keys with ssh-agent" test.
Replace the openssh BR added in e8896ce (update to 2.34.0, 2021-11-15)
with openssh-clients. The latter requires the former.
Apply Taylor Blau's patch to fix a use-after-free bug in fmt-merge-msg¹.
Add `missing !LONG_IS_64BIT,EXPENSIVE` to git.skip-test-patterns. It is
used in t1051-large-conversion after upstream 596b5e77c9 (clean/smudge:
allow clean filters to process extremely large files, 2021-11-02).
Release notes:
https://github.com/git/git/raw/v2.35.0-rc0/Documentation/RelNotes/2.35.0.txt
¹ https://lore.kernel.org/git/CAHk-=whXPxWL7z3GiPkaDt+yygrRmagrYUnib7Lx=Vvrqx2ufg@mail.gmail.com/
