Remove random seed initializer

[tleyden]

I just stumbled upon https://github.com/couchbase/cbgt/blob/master/misc.go#L32

func init() {
	rand.Seed(time.Now().UTC().UnixNano())
}

from the git history it looks like I had added it at some point.

I think it might have been accidentally pushed as a temporary workaround for https://issues.couchbase.com/browse/MB-24237?focusedCommentId=214133, and it should probably get removed per @mschoch's comment about libraries not touching the global random seed.