[#561] DashboardServer: Desktop#isDesktopSupported passes on headless…

… systems (#580)

`Desktop.isDesktopSupported()` is used in the DashboardServer to check
for the Desktop environment prior to the launching of dashboard.

However, in a headless system, this check will return true
irregardless, resulting in an uncaught run time exception to be thrown.

To ensure that this action is truly supported by the executing
environment, let's add an additional condition to ensure that the
instance supports browsing action.

src/main/java/reposense/system/DashboardServer.java

@@ -45,7 +45,7 @@ public static void startServer(int port, Path requestPath) {
      */
     private static void launchBrowser(String url) throws IOException {
         try {
-            if (Desktop.isDesktopSupported()) {
+            if (Desktop.isDesktopSupported() && Desktop.getDesktop().isSupported(Desktop.Action.BROWSE)) {
                 Desktop.getDesktop().browse(new URI(url));
                 logger.info("Loading " + url + " on the default browser...");
             } else {