opal: Segfault avoidence in class and mca/btl/ofi

Fixed a loop causing segfaults in opal_object.h and fixed goto fail
block to check for NULL before potential dereference as we go there
for NULL in what we dereference

Signed-off-by: Josh Fisher <josh.fisher@cornelisnetworks.com>

opal/class/opal_object.h

@@ -479,7 +479,7 @@ static inline void opal_obj_run_destructors(opal_object_t * object)
     assert(NULL != object->obj_class);
 
     cls_destruct = object->obj_class->cls_destruct_array;
-    while( NULL != *cls_destruct ) {
+    while (NULL != cls_destruct && NULL != *cls_destruct) {
         (*cls_destruct)(object);
         cls_destruct++;
     }

opal/mca/btl/ofi/btl_ofi_component.c

@@ -675,8 +675,10 @@ static int mca_btl_ofi_init_device(struct fi_info *info)
 
     /* if the contexts have not been initiated, num_contexts should
      * be zero and we skip this. */
-    for (int i=0; i < module->num_contexts; i++) {
-        mca_btl_ofi_context_finalize(&module->contexts[i], module->is_scalable_ep);
+    if (NULL != module->contexts) {
+        for (int i = 0; i < module->num_contexts; i++) {
+            mca_btl_ofi_context_finalize(&module->contexts[i], module->is_scalable_ep);
+        }
     }
     free(module->contexts);