Add barrier() to avoid unit test race condition
Add barrier() to avoid unit test race condition

We don't want to try reading a file on any processor until we're sure
all processors are done writing that file.

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