refresh connection capabilities even if connection was already established

This is relevant for he Ledger Nano S, which may change "key slots"
interactively.

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/SecurityTokenConnection.java

@@ -90,6 +90,7 @@ public class SecurityTokenConnection {
 
     public void connectIfNecessary(Context context) throws IOException {
         if (isConnected()) {
+            refreshConnectionCapabilities();
             return;
         }