tests: Improve pki_import_privkey_base64 test.
tests: Improve pki_import_privkey_base64 test.

sebadoom/libssh,mwgoldsmith/ssh,DouglasHeriot/libssh,mwgoldsmith/libssh,jt1/honeypot-libssh,bigcat26/libssh-mod,nviennot/libssh,Distrotech/libssh,kedazo/libssh,DouglasHeriot/libssh,taikoo/libssh,jt1/honeypot-libssh,nviennot/libssh,pouete/libssh,taikoo/libssh,nviennot/libssh,bigcat26/libssh-mod,elastichosts/libssh,Distrotech/libssh,wangshawn/libssh,taikoo/libssh,mwgoldsmith/libssh,mwgoldsmith/libssh,wangshawn/libssh,elastichosts/libssh,DouglasHeriot/libssh,robxu9/libssh,kedazo/libssh,bigcat26/libssh-mod,Distrotech/libssh,robxu9/libssh,nviennot/libssh,bigcat26/libssh-mod,mwgoldsmith/libssh,pouete/libssh,robxu9/libssh,elastichosts/libssh,mwgoldsmith/ssh,pouete/libssh,pouete/libssh,wangshawn/libssh,jt1/honeypot-libssh,mwgoldsmith/ssh,robxu9/libssh,jt1/honeypot-libssh,sebadoom/libssh,DouglasHeriot/libssh,sebadoom/libssh,wangshawn/libssh,sebadoom/libssh,kedazo/libssh,taikoo/libssh,mwgoldsmith/ssh,Distrotech/libssh,kedazo/libssh