virCapabilitiesHostNUMAAddCell: Take double pointer

What this function really does it takes ownership of all pointers
passed (well, except for the first one - caps - to which it
registers new NUMA node). But since all info is passed as a
single pointer it's hard to tell (and use g_auto*). Let's use
double pointers to make the ownership transfer obvious.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

tests/testutils.c

@@ -935,9 +935,9 @@ virTestCapsBuildNUMATopology(int seq)
 
         virCapabilitiesHostNUMAAddCell(caps, cell_id + seq,
                                        MAX_MEM_IN_CELL,
-                                       MAX_CPUS_IN_CELL, cell_cpus,
-                                       VIR_ARCH_NONE, NULL,
-                                       VIR_ARCH_NONE, NULL);
+                                       MAX_CPUS_IN_CELL, &cell_cpus,
+                                       0, NULL,
+                                       0, NULL);
 
         cell_cpus = NULL;
     }