Set error code on alloc failures

Almost all *alloc failures now set an error code.

Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/5842)
diff --git a/ssl/pqueue.c b/ssl/pqueue.c
index ee64eb3..3787d26 100644
--- a/ssl/pqueue.c
+++ b/ssl/pqueue.c
@@ -18,14 +18,15 @@
 pitem *pitem_new(unsigned char *prio64be, void *data)
 {
     pitem *item = OPENSSL_malloc(sizeof(*item));
-    if (item == NULL)
+
+    if (item == NULL) {
+        SSLerr(SSL_F_PITEM_NEW, ERR_R_MALLOC_FAILURE);
         return NULL;
+    }
 
     memcpy(item->priority, prio64be, sizeof(item->priority));
-
     item->data = data;
     item->next = NULL;
-
     return item;
 }
 
@@ -38,6 +39,9 @@
 {
     pqueue *pq = OPENSSL_zalloc(sizeof(*pq));
 
+    if (pq == NULL)
+        SSLerr(SSL_F_PQUEUE_NEW, ERR_R_MALLOC_FAILURE);
+
     return pq;
 }