r.kappa: fix qsort cmp fn (see https://trac.osgeo.org/grass/ticket/3564)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@73138 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.kappa/prt_mat.c

@@ -206,8 +206,8 @@ static int longcomp(const void *aa, const void *bb)
     const long *a = aa;
     const long *b = bb;
 
-    if (*a != *b)
-	return (*a > *b ? 1 : -1);
+    if (*a < *b)
+	return -1;
 
-    return 0;
+    return (*a > *b);
 }