message: In ex12p.cpp, update the random seeds in some of the sample runs
  to avoid getting spurious eigenvalues or convergence failures.
diff: // Sample runs:
  // mpirun -np 4 ex12p -m ../data/beam-tri.mesh
  // mpirun -np 4 ex12p -m ../data/beam-quad.mesh
  -// mpirun -np 4 ex12p -m ../data/beam-tet.mesh -s 79 -n 10 -o 2 -elast
  -// mpirun -np 4 ex12p -m ../data/beam-hex.mesh -s 3876
  -// mpirun -np 4 ex12p -m ../data/beam-wedge.mesh -s 79
  +// mpirun -np 4 ex12p -m ../data/beam-tet.mesh -s 462 -n 10 -o 2 -elast
  +// mpirun -np 4 ex12p -m ../data/beam-hex.mesh -s 3878
  +// mpirun -np 4 ex12p -m ../data/beam-wedge.mesh -s 81
  // mpirun -np 4 ex12p -m ../data/beam-tri.mesh -s 3876 -o 2 -sys
  -// mpirun -np 4 ex12p -m ../data/beam-quad.mesh -s 4526 -n 6 -o 3 -elast
  +// mpirun -np 4 ex12p -m ../data/beam-quad.mesh -s 4544 -n 6 -o 3 -elast
  // mpirun -np 4 ex12p -m ../data/beam-quad-nurbs.mesh
  // mpirun -np 4 ex12p -m ../data/beam-hex-nurbs.mesh
  //
  