Refactor XdrIO::write_serialized_connectivity().
Refactor XdrIO::write_serialized_connectivity().

Don't re-use iterators multiple times throughout the algorithm, it
just makes it harder to follow the flow of the code.

hrittich/libmesh,capitalaslash/libmesh,pbauman/libmesh,90jrong/libmesh,libMesh/libmesh,dschwen/libmesh,pbauman/libmesh,libMesh/libmesh,BalticPinguin/libmesh,hrittich/libmesh,90jrong/libmesh,90jrong/libmesh,capitalaslash/libmesh,hrittich/libmesh,libMesh/libmesh,libMesh/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,dschwen/libmesh,libMesh/libmesh,90jrong/libmesh,roystgnr/libmesh,pbauman/libmesh,capitalaslash/libmesh,giorgiobornia/libmesh,roystgnr/libmesh,giorgiobornia/libmesh,90jrong/libmesh,roystgnr/libmesh,BalticPinguin/libmesh,capitalaslash/libmesh,giorgiobornia/libmesh,roystgnr/libmesh,capitalaslash/libmesh,libMesh/libmesh,dschwen/libmesh,90jrong/libmesh,BalticPinguin/libmesh,hrittich/libmesh,BalticPinguin/libmesh,roystgnr/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,dschwen/libmesh,roystgnr/libmesh,giorgiobornia/libmesh,90jrong/libmesh,hrittich/libmesh,dschwen/libmesh,roystgnr/libmesh,capitalaslash/libmesh,capitalaslash/libmesh,pbauman/libmesh,libMesh/libmesh,jwpeterson/libmesh,giorgiobornia/libmesh,hrittich/libmesh,hrittich/libmesh,jwpeterson/libmesh,dschwen/libmesh,90jrong/libmesh,pbauman/libmesh,roystgnr/libmesh,jwpeterson/libmesh,capitalaslash/libmesh,pbauman/libmesh,BalticPinguin/libmesh,dschwen/libmesh,jwpeterson/libmesh,dschwen/libmesh,giorgiobornia/libmesh,jwpeterson/libmesh,libMesh/libmesh,hrittich/libmesh,90jrong/libmesh,giorgiobornia/libmesh,giorgiobornia/libmesh,BalticPinguin/libmesh,hrittich/libmesh,pbauman/libmesh,pbauman/libmesh,jwpeterson/libmesh,giorgiobornia/libmesh,pbauman/libmesh