rref returns wrong results for sparse matrices

[John W. Eaton]

On  4-Mar-2008, David Bateman wrote:

| Jaroslav Hajek wrote:
| > I've tracked this problem down to the statement
| > 	A ([pivot, r], c:cols) = A ([r, pivot], c:cols);
| >
| > which apparently confuses Octave when pivot == r. The attached
| > changeset is a quickfix for this; however, according to what John
| > observed there may be bugs buried more deeply in liboctave.
| >
| >   
| I believe the attached is a fix for this issue that addresses it within
| the sparse assignment operators.

I applied it to the main and 3.0.x branches of my archive.

Thanks,

jwe