Bug#45611: Minor code cleanup

Remove a self assignment.
Rework a few constructs to avoid a potential overflow.

Based upon patch contributed by Michal Hrusecky

storage/ndb/src/kernel/blocks/dbdict/Dbdict.cpp

@@ -7521,8 +7521,8 @@ void Dbdict::execGET_TABINFOREQ(Signal* signal)
       return;
     }
     releaseSections(signal);
-    
-    DictObject * old_ptr_p = old_ptr_p = get_object(tableName, len);
+
+    DictObject * old_ptr_p = get_object(tableName, len);
     if(old_ptr_p)
       obj_id = old_ptr_p->m_id;
   } else {

storage/ndb/src/mgmsrv/InitConfigFileParser.cpp

@@ -208,11 +208,10 @@ InitConfigFileParser::run_config_rules(Context& ctx)
   ctx.m_config->put("NoOfNodes", nNodes);
 
   char tmpLine[MAX_LINE_LENGTH];
-  BaseString::snprintf(tmpLine, MAX_LINE_LENGTH, "EXTERNAL SYSTEM_");
-  strncat(tmpLine, system, MAX_LINE_LENGTH);
-  strncat(tmpLine, ":NoOfConnections", MAX_LINE_LENGTH);
+  BaseString::snprintf(tmpLine, MAX_LINE_LENGTH,
+                       "EXTERNAL SYSTEM_%s:NoOfConnections", system);
   ctx.m_config->put(tmpLine, nExtConnections);
-  
+
   Config * ret = new Config();
   ret->m_configValues = (struct ndb_mgm_configuration*)ctx.m_configValues.getConfigValues();
   ret->m_oldConfig = ctx.m_config; ctx.m_config = 0;