atpoints - fix diagonal bug with stale qvec data

[jeremylt]

CG is too good and accounts for bugs that aren't too big, this is a better fix

  0 SNES Function norm 7.981366173789e-03
    0 KSP Residual norm 1.906739256988e-02
    1 KSP Residual norm 1.133026883989e-02
    2 KSP Residual norm 6.193022690644e-03
    3 KSP Residual norm 1.387872543034e-03
    4 KSP Residual norm 3.211734455270e-04
    5 KSP Residual norm 1.478256477347e-04
    6 KSP Residual norm 9.712677425269e-05
    7 KSP Residual norm 6.158649485781e-05
    8 KSP Residual norm 3.967832285086e-05
    9 KSP Residual norm 2.146662731434e-05
   10 KSP Residual norm 8.908305678412e-06
   11 KSP Residual norm 4.275244854390e-06
   12 KSP Residual norm 1.596758075922e-06
   13 KSP Residual norm 3.743327669677e-07
   14 KSP Residual norm 1.202134006077e-07
  1 SNES Function norm 4.231286222104e-08
    0 KSP Residual norm 1.202134006065e-07
    1 KSP Residual norm 4.497892037491e-08
    2 KSP Residual norm 1.474816907980e-08
    3 KSP Residual norm 8.383450566003e-09
    4 KSP Residual norm 4.658905611034e-09
    5 KSP Residual norm 3.474702905544e-09
    6 KSP Residual norm 2.552378821076e-09
    7 KSP Residual norm 1.843846827831e-09
    8 KSP Residual norm 6.346014153950e-10
    9 KSP Residual norm 3.798572942618e-10
   10 KSP Residual norm 1.569768492542e-10
   11 KSP Residual norm 5.736853440592e-11
   12 KSP Residual norm 2.383221609152e-11
   13 KSP Residual norm 5.452571943714e-12
   14 KSP Residual norm 6.995826921566e-13
  2 SNES Function norm 3.536200451966e-13