New radius_paircreate() function that takes a REQUEST* and a

	New radius_paircreate() function that takes a REQUEST* and a
	VALUE_PAIR**, along with the attr & type of paircreate().

	It creates the pair (or exits if it can't, because it's OOM).
	then adds the pair to the VP**.

	This ends up removing a fair amount of code in the modules &&
	server core, that did:

	vp = pairmake()
	if (!vp) {
		oom
		...
	}

	pairadd()