Remove unused memberservice api doc

The memberservice is already moved out as fabric-cop.

Change-Id: I2183dcd557f63ee8bc1fbdd1c9276ce4daac57d0
Signed-off-by: Baohua Yang <[email protected]>

Author: yeasy

docs/API/MemberServicesAPI.md

@@ -25,7 +25,6 @@ pages:
 - API's:
   - Chaincode APIs: API/ChaincodeAPI.md
   - Command Line Interface: API/CLI.md
-  - CA API: API/MemberServicesAPI.md
 
 - Fabric Developer:
   - v1.0 Preview: abstract_v1.md