Fix nullpointer exception with unsupported URL protocol #1237

Author: Martin Spielmann

src/main/java/com/gitblit/manager/ServicesManager.java

@@ -276,7 +276,7 @@ public int compare(RepositoryUrl o1, RepositoryUrl o2) {
 			Iterator<RepositoryUrl> itr = list.iterator();
 			while (itr.hasNext()) {
 				RepositoryUrl url = itr.next();
-				if (url.transport.equals(preferredTransport)) {
+				if (url.transport != null && url.transport.equals(preferredTransport)) {
 					itr.remove();
 					preferredUrl = url;
 					break;