OpenSSH has deprecated its use of scp/rcp protocol in favor of SFTP,
which the embedded Apache mina-sshd in widely-deployed Gerrit
versions does not yet support. The default officially changed in
OpenSSH 9.0 (some distributions, such as Fedora and CentOS, switched
their default behavior to this as early as OpenSSH 8.7 or 8.8),
leading to a ``subsystem request failed on channel 0`` error during
commit-msg hook retrieval. Now git-review will attempt to detect
whether scp's -O option is available to force use of the legacy
scp/rcp protocol, and apply it if so.
Change-Id: Ib64c03c3e12a3a8390e38f6ca9393db3b3c2a9e3
5bfaa4a6f3