dchat: fix mistakes on default config

example/dchat/dchatd/dchatd_config.toml

@@ -1,14 +1,14 @@
 # dchat toml
 
 ## RPC listen address. 
-rpc_listen =["tcp://127.0.0.1:51054"]
+rpc_listen="tcp://127.0.0.1:51054"
 
 [net]
 ## P2P accept addresses Required for inbound nodes.
 #inbound=["tcp://127.0.0.1:51554"]
 
 ## P2P external addresses. Required for inbound nodes.
-#external_addr=["tcp://127.0.0.1:51554"]
+#external_addrs=["tcp://127.0.0.1:51554"]
 
 ## Seed nodes to connect to. Required for inbound and outbound nodes.
 seeds=["tcp://127.0.0.1:50515"]