Loosen key file format spec slightly
Loosen key file format spec slightly

Some versions of OpenSSL, including the version on Travis, leave out the "RSA".

duypq94/heroku,dickeyxxx/heroku,greeca0204/heroku,vcgato29/heroku,macedo/heroku,gregburek/heroku,rkh/heroku,gregburek/heroku,greeca0204/heroku,duypq94/heroku,dickeyxxx/heroku,sancopanco/heroku,Faisalawanisee/heroku,rkh/heroku,sancopanco/heroku,macedo/heroku,macedo/heroku,greeca0204/heroku,vcgato29/heroku,Faisalawanisee/heroku,dickeyxxx/heroku,Faisalawanisee/heroku,duypq94/heroku,gregburek/heroku,rkh/heroku,sancopanco/heroku,vcgato29/heroku