Shells only have 2 faces
Shells only have 2 faces

And now that we're relying on that fact implicitly in ParallelElem and
BoundaryInfo::copy_boundary_ids(), we should assert it explicitly to
protect ourselves from users who may disagree.

giorgiobornia/libmesh,libMesh/libmesh,dschwen/libmesh,capitalaslash/libmesh,aeslaughter/libmesh,90jrong/libmesh,benkirk/libmesh,balborian/libmesh,aeslaughter/libmesh,jwpeterson/libmesh,friedmud/libmesh,vikramvgarg/libmesh,pbauman/libmesh,dschwen/libmesh,libMesh/libmesh,coreymbryant/libmesh,hrittich/libmesh,BalticPinguin/libmesh,svallaghe/libmesh,dschwen/libmesh,roystgnr/libmesh,balborian/libmesh,friedmud/libmesh,coreymbryant/libmesh,pbauman/libmesh,BalticPinguin/libmesh,dschwen/libmesh,friedmud/libmesh,svallaghe/libmesh,capitalaslash/libmesh,vikramvgarg/libmesh,giorgiobornia/libmesh,libMesh/libmesh,roystgnr/libmesh,svallaghe/libmesh,aeslaughter/libmesh,giorgiobornia/libmesh,90jrong/libmesh,friedmud/libmesh,coreymbryant/libmesh,svallaghe/libmesh,capitalaslash/libmesh,coreymbryant/libmesh,svallaghe/libmesh,vikramvgarg/libmesh,giorgiobornia/libmesh,capitalaslash/libmesh,capitalaslash/libmesh,90jrong/libmesh,friedmud/libmesh,svallaghe/libmesh,vikramvgarg/libmesh,benkirk/libmesh,pbauman/libmesh,BalticPinguin/libmesh,90jrong/libmesh,libMesh/libmesh,aeslaughter/libmesh,jwpeterson/libmesh,friedmud/libmesh,hrittich/libmesh,vikramvgarg/libmesh,pbauman/libmesh,dschwen/libmesh,svallaghe/libmesh,benkirk/libmesh,benkirk/libmesh,hrittich/libmesh,aeslaughter/libmesh,balborian/libmesh,libMesh/libmesh,90jrong/libmesh,BalticPinguin/libmesh,capitalaslash/libmesh,aeslaughter/libmesh,aeslaughter/libmesh,hrittich/libmesh,BalticPinguin/libmesh,capitalaslash/libmesh,vikramvgarg/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,90jrong/libmesh,coreymbryant/libmesh,hrittich/libmesh,libMesh/libmesh,BalticPinguin/libmesh,svallaghe/libmesh,roystgnr/libmesh,hrittich/libmesh,jwpeterson/libmesh,balborian/libmesh,coreymbryant/libmesh,dschwen/libmesh,90jrong/libmesh,balborian/libmesh,aeslaughter/libmesh,pbauman/libmesh,coreymbryant/libmesh,jwpeterson/libmesh,friedmud/libmesh,hrittich/libmesh,benkirk/libmesh,vikramvgarg/libmesh,roystgnr/libmesh,90jrong/libmesh,friedmud/libmesh,roystgnr/libmesh,svallaghe/libmesh,BalticPinguin/libmesh,giorgiobornia/libmesh,benkirk/libmesh,roystgnr/libmesh,balborian/libmesh,90jrong/libmesh,jwpeterson/libmesh,vikramvgarg/libmesh,BalticPinguin/libmesh,dschwen/libmesh,libMesh/libmesh,coreymbryant/libmesh,pbauman/libmesh,benkirk/libmesh,giorgiobornia/libmesh,pbauman/libmesh,libMesh/libmesh,benkirk/libmesh,aeslaughter/libmesh,roystgnr/libmesh,balborian/libmesh,dschwen/libmesh,balborian/libmesh,jwpeterson/libmesh,hrittich/libmesh,benkirk/libmesh,pbauman/libmesh,pbauman/libmesh,balborian/libmesh,giorgiobornia/libmesh,giorgiobornia/libmesh,vikramvgarg/libmesh,hrittich/libmesh,giorgiobornia/libmesh,capitalaslash/libmesh,friedmud/libmesh,balborian/libmesh,roystgnr/libmesh