Update random_bytes() to conform to PHP7.0.0-RC3
Update random_bytes() to conform to PHP7.0.0-RC3

Fixes #843

paragonie-scott/phpseclib,metaclassing/phpseclib,splitice/phpseclib,metaclassing/phpseclib,paragonie-scott/phpseclib,terrafrost/phpseclib,splitice/phpseclib,danog/phpseclib,phpseclib/phpseclib,danog/phpseclib