doc: Fix typos in sftp tutorial
doc: Fix typos in sftp tutorial

Thanks to Anthony Baker <AnthonyBaker@fico.com>

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

nviennot/libssh,kedazo/libssh,pouete/libssh,sebadoom/libssh,pouete/libssh,kedazo/libssh,pouete/libssh,sebadoom/libssh,sebadoom/libssh,nviennot/libssh,nviennot/libssh,kedazo/libssh,kedazo/libssh,nviennot/libssh,sebadoom/libssh,pouete/libssh