avoid divide by 0 for explicit sytems
avoid divide by 0 for explicit sytems

git-svn-id: e88a1e38e13faf406e05cc89eca8dd613216f6c4@4355 434f946d-2f3d-0410-ba4c-cb9f52fb0dbf

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