Add openmp flag to PETSc update script
Add openmp flag to PETSc update script

This fixes the PETSc build when using only the new moose-mpich package, 
where MUMPS was failing due to missing OpenMP symbols.

lindsayad/moose,idaholab/moose,andrsd/moose,dschwen/moose,laagesen/moose,dschwen/moose,lindsayad/moose,jessecarterMOOSE/moose,harterj/moose,sapitts/moose,lindsayad/moose,nuclear-wizard/moose,nuclear-wizard/moose,dschwen/moose,jessecarterMOOSE/moose,idaholab/moose,nuclear-wizard/moose,idaholab/moose,idaholab/moose,milljm/moose,lindsayad/moose,bwspenc/moose,harterj/moose,sapitts/moose,sapitts/moose,andrsd/moose,dschwen/moose,bwspenc/moose,idaholab/moose,nuclear-wizard/moose,milljm/moose,sapitts/moose,sapitts/moose,laagesen/moose,laagesen/moose,bwspenc/moose,dschwen/moose,jessecarterMOOSE/moose,milljm/moose,lindsayad/moose,laagesen/moose,jessecarterMOOSE/moose,andrsd/moose,harterj/moose,andrsd/moose,harterj/moose,laagesen/moose,andrsd/moose,jessecarterMOOSE/moose,harterj/moose,bwspenc/moose,bwspenc/moose,milljm/moose,milljm/moose