remove auth packet end verification
remove auth packet end verification

not consistens for all MySQL versions:

http://dev.mysql.com/doc/internals/en/connection-phase.html#packet-Protocol::Handshake

Closes #75

methane/mysql,VividCortex/mysql,Vorstack/mysql,LightKool/mysql-go,LightKool/mysql-go,jockchou/mysql,henrylee2cn/mysql,VividCortex/mysql,netroby/mysql,yonglehou/mysql,nanata1115/mysql,tmulchay/mysql,hyperworks/mysql,segmentio/mysql,Freeaqingme/golang-sql-driver-mysql,eklitzke/mysql,siriele/mysql,chinanjjohn2012/mysql,hebihui/mysql,methane/mysql,joshuaprunier/mysql,helight/helight_code,muthusubbu459/mysql,Go-SQL-Driver/MySQL,segmentio/mysql,bookerzzz/mysql,helight/helight_code,helight/helight_code,dalinaum/go-mysql-driver,aperera/mysql,Frca/mysql,rlowe/mysql,cxflag203/mysql,sunjian1/mysql,helight/helight_code,cw2018/mysql,zhgo/mysql,eXcomm/gomysql,beego/mysql,helight/helight_code,helight/helight_code,bookerzzz/mysql,rafaeljusto/mysql,springning/mysql,yyljlyy/mysql,roth1002/mysql,go-sql-driver/mysql,helight/helight_code,helight/helight_code,wfxiang08/mysql,helight/helight_code