op-guide: fix a typo in deployment with docker (pingcap#75)

Author: iamxy

op-guide/docker-deployment.md

@@ -160,7 +160,7 @@ mysql> show databases;
 
 The TiKV and PD can be started with a specified configuration file, which includes some advanced parameters, for the performance tuning.
 
-Assume that the path to configuration file of PD and TiKV on the host is `/path/to/config/pd.toml` and `／path/to/config/tikv.toml`
+Assume that the path to configuration file of PD and TiKV on the host is `/path/to/config/pd.toml` and `/path/to/config/tikv.toml`
 
 You can start TiKV and PD as follows: