[Authentication] Added more logs for token validation error

Authentication/Business/JWT/TokenValidationHandler.cs

                 var salt = ((ClaimsIdentity)claim.Identity).Claims.FirstOrDefault(x => x.Type == ClaimTypes.Authentication);
 
                 if (name == null || salt == null)
+                {
+                    OpResult<bool>.Error(ResultStatus.LoginError, string.Format("Incomplete token; username is present: {0}; salt is present {1}", name != null, salt != null)).Log();
                     statusCode = HttpStatusCode.Unauthorized;
+                }
                 else
                 {
                     var user = GetUserDbo(name.Value, salt.Value);
                     if (user == null)
+                    {
+                        OpResult<bool>.Error(ResultStatus.LoginError,
+                            string.Format("Username {0} not found", name.Value)).Log();
                         statusCode = HttpStatusCode.Unauthorized;
+                    }
                     else
                     {
                         UserStorage.BasicUserDbo = user;