client: Fix ssh_send_banner() to confirm with RFC 4253
client: Fix ssh_send_banner() to confirm with RFC 4253

Signed-off-by: Andreas Schneider <5be00ddc76278cf6077f5047ca3384a88460c671@cryptomilk.org>

kedazo/libssh,kedazo/libssh,kedazo/libssh,kedazo/libssh