Simplify Fluidity to PETSc data routines
Simplify Fluidity to PETSc data routines

Now that there is no distinction between DG and CG assembly types, the
insertion action and insertion rows for moving from Fluidity to PETSc
data are always the same (private rows, INSERT_VALUES), so no need for
intermediate variables handling them.

jjo31/ATHAM-Fluidity,jrper/fluidity,iakovos-panourgias/fluidity,rjferrier/fluidity,iakovos-panourgias/fluidity,iakovos-panourgias/fluidity,rjferrier/fluidity,jjo31/ATHAM-Fluidity,jrper/fluidity,rjferrier/fluidity,iakovos-panourgias/fluidity,rjferrier/fluidity,jrper/fluidity,jjo31/ATHAM-Fluidity,jjo31/ATHAM-Fluidity,jrper/fluidity,jjo31/ATHAM-Fluidity,rjferrier/fluidity,jrper/fluidity,iakovos-panourgias/fluidity