Changing maxPasswordLength to 20

Changed maxPasswordLength to 20 as per
documentation.

Tested by:
 - Checked redfish account properties
   response and observed change value.

Signed-off-by: AppaRao Puli <apparao.puli@linux.intel.com>
Change-Id: If1a963c29381bb7feb431f7e9b270b4432b72f9d
diff --git a/redfish-core/lib/account_service.hpp b/redfish-core/lib/account_service.hpp
index 1b7b4b8..9365ebb 100644
--- a/redfish-core/lib/account_service.hpp
+++ b/redfish-core/lib/account_service.hpp
@@ -102,7 +102,7 @@
             {"Name", "Account Service"},
             {"Description", "Account Service"},
             {"ServiceEnabled", true},
-            {"MaxPasswordLength", 31},
+            {"MaxPasswordLength", 20},
             {"Accounts",
              {{"@odata.id", "/redfish/v1/AccountService/Accounts"}}},
             {"Roles", {{"@odata.id", "/redfish/v1/AccountService/Roles"}}}};