cmake: Fixed ZLIB configure check.
cmake: Fixed ZLIB configure check.

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