BUG: searchsorted fails if sorter is not of type np.intp fixes #4698

The array being passed to the search function was not the one converted
to NPY_INTP, so it only worked if it was of that type to begin with.
Merge pull request #4708 from jaimefrio/sorter-bug

BUG: searchsorted fails if sorter is not of type np.intp fixes #4698