Tests/RSA: re-added accidentally removed $rsa initialization
Tests/RSA: re-added accidentally removed $rsa initialization

metaclassing/phpseclib,paragonie-scott/phpseclib,danog/phpseclib,thaigialai1987/phpseclib,creatuity/phpseclib,creatuity/phpseclib,kenichiii/phpseclib,danog/phpseclib,metaclassing/phpseclib,splitice/phpseclib,kenichiii/phpseclib,splitice/phpseclib,phpseclib/phpseclib,paragonie-scott/phpseclib,thaigialai1987/phpseclib,terrafrost/phpseclib