Problems with `ntpd` initial time sync in `gentoo-install.sh`

[kristapsk]

1. User may not have ntpd, if running install from some other Linux environment, not Gentoo LiveCD.

2. Sometimes ntpd fails, that maybe should not abort script (although we want for time be in sync, need to look at alternative methods).

3. There is net-misc/ntp and net-misc/openntpd, their parameters differ.