Updated libssh2 packages fix security vulnerability

Andreas Schneider reported that libssh2 passes the number of bytes to a function that expects number of bits during the SSHv2 handshake when libssh2 is to get a suitable value for ‘group order’ in the Diffie-Hellman negotiation. This weakens significantly the handshake security, potentially allowing an eavesdropper with enough resources to decrypt or intercept SSH sessions (CVE-2016-0787).