Update csi-debug.md

Author: andyzhangx

docs/csi-debug.md

@@ -91,7 +91,7 @@ mount | grep blobfuse | uniq
 ```
 
  - Troubleshooting blobfuse mount failure on the agent node
-   - collect log files: `/var/log/messages`, `/var/log/blobfuse*.log`
+   - collect log files: `/var/log/messages`, `/var/log/syslog`, `/var/log/blobfuse*.log`
 
 ### troubleshooting connection failure on agent node
  - blobfuse