The rules of the Foreign Relations Committee are at:
http://foreign.senate.gov/rule.html
Rule 4 — Quorums
(a) Testimony. — For the purpose of taking sworn or unsworn testimony at any duly scheduled meeting a quorum of the Committee and each subcommittee thereof shall consist of one member.
(b) Business. — A quorum for the transaction of Committee or subcommittee business, other than for reporting a measure or recommendation to the Senate or the taking of testimony, shall consist of one-third of the members of the Committee or subcommittee, including at least one member from each party.
(c) Reporting. — A majority of the membership of the Committee shall constitute a quorum for reporting any measure or recommendation to the Senate. No measure or recommendation shall be ordered reported from the Committee unless a majority of the Committee members are physically present. The vote of the Committee to report a measure or matter shall require the concurrence of a majority of those members who are physically present at the time the vote is taken.
From Rule 4-c it looks like the committee could just send Bolton's nomination to the floor as long as all of the Republicans showed up for the meeting and six of them voted in favor.
But then, I'm not a lawyer - or a parliamentarian.