void
rdataFromString(Tokenizer st, Name origin) throws IOException {
	u16Field = st.getUInt16();
	nameField = st.getName(origin);
}
Implements common functionality for the many record types whose format
is an unsigned 16 bit integer followed by a name.

@author Brian Wellington
src/main/java/core/org/xbill/DNS/U16NameBase.java