Add more error checks to sig_verify().
Add more error checks to sig_verify().


git-svn-id: b1dee0d48e635e16c3b356ce77271b225d4db9f7@511 7dcaeef0-15fb-0310-b436-a5af3365683c

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