Update INSTALL.md
Update INSTALL.md

While following your guide I received "Unable to locate package ntpd"

I googled and found that apt-get ntp works instead.
habibmasuro/coinpunk,eXcomm/coinpunk,kyledrake/coinpunk,dayreiner/quarkpunk,bitpay/coinpunk,Bushstar/featherpunk,eXcomm/coinpunk,Bushstar/talentpunk,RaitoBezarius/coinpunk,Bushstar/coinpunk,kyledrake/coinpunk,offlinehacker/coinpunk,habibmasuro/coinpunk,RaitoBezarius/coinpunk,RobertStuff/coinpunk,Bushstar/coinpunk,Tetpay/coinpunk