socket: Make sure we only transmit data if we have some.
socket: Make sure we only transmit data if we have some.

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

wangshawn/libssh,sebadoom/libssh,rofl0r/libssh,miloj/libssh-v0.5,kedazo/libssh,substack/libssh,sebadoom/libssh,wangshawn/libssh,jt1/honeypot-libssh,jt1/honeypot-libssh,mwgoldsmith/ssh,bigcat26/libssh-mod,nviennot/libssh,DouglasHeriot/libssh,robxu9/libssh,substack/libssh,robxu9/libssh,elastichosts/libssh,mwgoldsmith/ssh,Distrotech/libssh,miloj/libssh-v0.5,nviennot/libssh,mwgoldsmith/libssh,substack/libssh,robxu9/libssh,pouete/libssh,DouglasHeriot/libssh,taikoo/libssh,elastichosts/libssh,kedazo/libssh,Distrotech/libssh,pouete/libssh,substack/libssh,jahrome/libssh,taikoo/libssh,mwgoldsmith/ssh,miloj/libssh-v0.5,miloj/libssh-v0.5,sebadoom/libssh,Distrotech/libssh,jt1/honeypot-libssh,mwgoldsmith/libssh,kedazo/libssh,Distrotech/libssh,taikoo/libssh,jt1/honeypot-libssh,mwgoldsmith/ssh,jahrome/libssh,nviennot/libssh,kedazo/libssh,bigcat26/libssh-mod,bigcat26/libssh-mod,wangshawn/libssh,rofl0r/libssh,DouglasHeriot/libssh,pouete/libssh,mwgoldsmith/libssh,robxu9/libssh,rofl0r/libssh,sebadoom/libssh,elastichosts/libssh,mwgoldsmith/libssh,nviennot/libssh,taikoo/libssh,rofl0r/libssh,DouglasHeriot/libssh,pouete/libssh,jahrome/libssh,jahrome/libssh,wangshawn/libssh,bigcat26/libssh-mod