client: Fix possible NULL pointer dereference.
client: Fix possible NULL pointer dereference.

elastichosts/libssh,kedazo/libssh,taikoo/libssh,kedazo/libssh,nviennot/libssh,wangshawn/libssh,robxu9/libssh,wangshawn/libssh,sebadoom/libssh,taikoo/libssh,DouglasHeriot/libssh,nviennot/libssh,taikoo/libssh,mwgoldsmith/libssh,mwgoldsmith/libssh,mwgoldsmith/ssh,robxu9/libssh,elastichosts/libssh,mwgoldsmith/libssh,mwgoldsmith/ssh,nviennot/libssh,bigcat26/libssh-mod,wangshawn/libssh,wangshawn/libssh,mwgoldsmith/libssh,sebadoom/libssh,bigcat26/libssh-mod,elastichosts/libssh,bigcat26/libssh-mod,sebadoom/libssh,pouete/libssh,mwgoldsmith/ssh,sebadoom/libssh,pouete/libssh,robxu9/libssh,DouglasHeriot/libssh,Distrotech/libssh,pouete/libssh,mwgoldsmith/ssh,pouete/libssh,taikoo/libssh,DouglasHeriot/libssh,Distrotech/libssh,nviennot/libssh,Distrotech/libssh,kedazo/libssh,robxu9/libssh,DouglasHeriot/libssh,kedazo/libssh,Distrotech/libssh,bigcat26/libssh-mod