Fix shouldReallocate function

[wengzf20]

In shouldReallocate function of memoryResource.H,

    bool shouldReallocate(gLabel nCells, gLabel nSpecie) const {

        if ((nCells != this->nCells()) ||
            (nSpecie != this->nSpecie()) ||
            (nCells + 2 != this->nEqns())) {
            return true;
        }
        return false;
    }

the nEqns should be nSpecie + 2 instead of nCells + 2.

The error results in momery reallocation every time step and lower the computation efficiency.

[hamsteri15]

Thanks for spotting this! Merged both.