BUG: 360af221 causes instabilities in kEpsilon

Run $FOAM_TUTORIALS/incompressible/simpleFoam/turbulentFlatPlate/Allrun with kEpsilon and grading_vs_yp[10]=130, grading_vs_yp[100]=5 only.

360af221 leads to failures for these yPlus={10,100} cases.

Related to #2642 (closed)

@andy

EDIT: Or the fix has just revealed the existing instability-prone behaviour in kEpsilon.

EDIT-2: The other tutorial that was affected: incompressible/simpleFoam/windAroundBuildings