add setUpClient when creating TlsConnectionHandler to prevent NullPointer

addons/reqesidta/src/main/java/org/openecard/addons/reqesidta/ssa/SsaHttpClient.java

@@ -75,6 +75,7 @@ public class SsaHttpClient implements SsaClient, Closeable {
 	    signUri = urlBuilder.addPathSegment("sign").build();
 
 	    tlsHandler = new TlsConnectionHandler(baseUri);
+	    tlsHandler.setUpClient();
 	} catch (MalformedURLException | URISyntaxException ex) {
 	    throw new IllegalArgumentException("Invalid SSA URL configured or specified.", ex);
 	}

addons/reqesidta/src/main/resources/reqesidta/default.properties

+# set to true when using prod
+# validate-server-cert = false
 validate-server-cert = true