Remove SetCredential(apikey) from base service

Author: mediumTaj

src/IBM.WatsonDeveloperCloud/Service/IWatsonService.cs

@@ -30,7 +30,6 @@ public interface IWatsonService
         string Password { get; set; }
 
         void SetCredential(string userName, string password);
-        void SetCredential(string apikey);
         void SetCredential(TokenOptions tokenOptions);
         void SetEndpoint(string endpoint);
     }

src/IBM.WatsonDeveloperCloud/Service/WatsonService.cs

@@ -92,19 +92,7 @@ public void SetCredential(string userName, string password)
             this.UserName = userName;
             this.Password = password;
         }
-
-        /// <summary>
-        /// Sets the apikey of the service. 
-        /// Also sets the endpoint if the user has not set the endpoint.
-        /// </summary>
-        /// <param name="apikey"></param>
-        public void SetCredential(string apikey)
-        {
-            this.ApiKey = apikey;
-            if (!_userSetEndpoint)
-                this.Endpoint = "https://gateway-a.watsonplatform.net/visual-recognition/api";
-        }
-
+        
         /// <summary>
         /// Sets the tokenOptions for the service. 
         /// Also sets the endpoint if the user has not set the endpoint.