fixed IDENTITY crisis

mysql-test/r/identity.result

+last_insert_id(345)
+345
+@@IDENTITY	last_insert_id()
+345	345

mysql-test/t/identity.test

+select last_insert_id(345);
+select @@IDENTITY,last_insert_id();

sql/sql_lex.cc

@@ -793,9 +793,19 @@ int yylex(void *arg)
       }
       break;
     case STATE_USER_END:		// end '@' of user@hostname
-      if (state_map[yyPeek()] != STATE_STRING &&
-	  state_map[yyPeek()] != STATE_USER_VARIABLE_DELIMITER)
-	lex->next_state=STATE_HOSTNAME;	// Mark for next loop     
+      switch (state_map[yyPeek()])
+      {
+      case STATE_STRING:
+      case STATE_USER_VARIABLE_DELIMITER:
+	break;
+      case STATE_USER_END:
+	lex->next_state=STATE_USER_END;
+	yySkip();
+	break;
+      default:
+	lex->next_state=STATE_HOSTNAME;
+	break;
+      }
       yylval->lex_str.str=(char*) lex->ptr;
       yylval->lex_str.length=1;
       return((int) '@');