openUpdateImage() should cleanup upon BADDIMS

[jamienoss]

The following code should cleanup correctly src:

...
/* get the dimensions and type */
        fits_get_img_dim(iodesc->ff, &no_dims, &status);
        fits_get_img_equivtype(iodesc->ff, &iodesc->type, &status);
        fits_get_img_size(iodesc->ff, 2, iodesc->dims, &status);
        if (status) {
            ioerr(BADDIMS, iodesc, status);
            return NULL;
        }
        if (no_dims == 2) {
            /* Nothing */
        } else if (no_dims == 1) {
            iodesc->dims[1] = 0;
        } else if (no_dims == 0) {
            iodesc->dims[0] = 0;
            iodesc->dims[1] = 0;
        } else {
            ioerr(BADDIMS, iodesc, 0);
            return NULL;
        }
...

should be:

...
/* get the dimensions and type */
        fits_get_img_dim(iodesc->ff, &no_dims, &status);
        fits_get_img_equivtype(iodesc->ff, &iodesc->type, &status);
        fits_get_img_size(iodesc->ff, 2, iodesc->dims, &status);
        if (status) {
            ioerr(BADDIMS, iodesc, status);
            free(iodesc->extname);
            free(iodesc->filename);
            free(iodesc);
            return NULL;
        }
        if (no_dims == 2) {
            /* Nothing */
        } else if (no_dims == 1) {
            iodesc->dims[1] = 0;
        } else if (no_dims == 0) {
            iodesc->dims[0] = 0;
            iodesc->dims[1] = 0;
        } else {
            ioerr(BADDIMS, iodesc, 0);
            free(iodesc->extname);
            free(iodesc->filename);
            free(iodesc);
            return NULL;
        }
...

There may be an existing helper func that could be used here.

In addition, the free(tmp) should also nullify tmp - src.

The above may not be everything needed.