Fix the unnecessary parameter

Signed-off-by: Kai Qiang Wu(Kennan) <wkqwu@cn.ibm.com>

docs/reference/api/docker_remote_api_v1.21.md

@@ -2575,7 +2575,7 @@ Instruct the driver to remove the volume (`name`).
 
 **Example request**:
 
-    DELETE /volumes/local/tardis HTTP/1.1
+    DELETE /volumes/tardis HTTP/1.1
 
 **Example response**:
 

docs/reference/api/docker_remote_api_v1.22.md

@@ -2814,7 +2814,7 @@ Instruct the driver to remove the volume (`name`).
 
 **Example request**:
 
-    DELETE /volumes/local/tardis HTTP/1.1
+    DELETE /volumes/tardis HTTP/1.1
 
 **Example response**: