BUG#15215 mysqld fails at start-up because of illegal reply from mgmd

In the rare circumstance where a mysqld connects to a mgm server, then the
mgm server goes away before a node id can be allocated, it was possible to get
an Error in mgm protocol parser error message.

ndb/src/common/mgmcommon/ConfigRetriever.cpp

@@ -341,9 +341,15 @@ ConfigRetriever::allocNodeId(int no_retries, int retry_delay_in_seconds)
   {
     while (1)
     {
+      if(!ndb_mgm_is_connected(m_handle))
+	if(!ndb_mgm_connect(m_handle, 0, 0, 0))
+	  goto next;
+
       int res= ndb_mgm_alloc_nodeid(m_handle, m_version, m_node_type);
       if(res >= 0)
 	return _ownNodeId= (Uint32)res;
+
+  next:
       if (no_retries == 0)
 	break;
       no_retries--;

ndb/src/mgmapi/mgmapi.cpp

@@ -336,10 +336,16 @@ ndb_mgm_call(NdbMgmHandle handle, const ParserRow<ParserDummy> *command_reply,
   const Properties* p = parser.parse(ctx, session);
   if (p == NULL){
     if(!ndb_mgm_is_connected(handle)) {
-      return NULL;
+      DBUG_RETURN(NULL);
     }
     else
     {
+      if(ctx.m_status==Parser_t::Eof
+	 || ctx.m_status==Parser_t::NoLine)
+      {
+	ndb_mgm_disconnect(handle);
+	DBUG_RETURN(NULL);
+      }
       /**
        * Print some info about why the parser returns NULL
        */