org.jboss.tools.runtime.ui.internal.wizard.DownloadRuntimeLicenseFragment fails with SWTError without browser available

DownloadRuntimeLicenseFragment should work even without browser widget available and show html or text without html tags with <p> and <br> elements replaced with '\n'.

Steps to tests the issue:
1. Linux disto without webkit or xulrunner (I was using xubuntu to verify)
2. Run JBT and try to download WildFly using Runtime Download dialog;
3. It should show not fail with SWTError when presenting license step, but show the link to the license, so you can click on it to open system browser or copy/past it into your favorite one
4. Close eclipse
5. Install libwebkit
6. Start eclipse, do WildFly downloading steps again and you should see license text inside dialog.