petsc-3.5: SNES_VI_(N)INF --> PETSC_(N)INFINITY
petsc-3.5: dropping explicit MatStructure argument and Mat indirection from KSP/PCSetOperators() and friends.
Merge pull request #206 from karpeev/petsc-3.5

petsc-3.5: SNES_VI_(N)INF --> PETSC_(N)INFINITY