fix exception with empty git repositories

scm-test/src/main/java/sonia/scm/repository/client/GitRepositoryClient.java

@@ -43,6 +43,7 @@ import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.dircache.DirCacheCheckout;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.errors.NoRemoteRepositoryException;
 import org.eclipse.jgit.errors.NotSupportedException;
 import org.eclipse.jgit.errors.TransportException;
 import org.eclipse.jgit.lib.Constants;
@@ -155,10 +156,14 @@ public class GitRepositoryClient implements RepositoryClient
     try
     {
       final FetchResult r = runFetch();
+
+      if (r != null)
+      {
         final Ref branch = guessHEAD(r);
 
         doCheckout(branch);
       }
+    }
     catch (Exception ex)
     {
       throw new RepositoryClientException(ex);
@@ -383,11 +388,17 @@ public class GitRepositoryClient implements RepositoryClient
    * @return
    *
    * @throws NotSupportedException
+   * @throws RepositoryClientException
    * @throws TransportException
    * @throws URISyntaxException
    */
   private FetchResult runFetch()
-          throws NotSupportedException, URISyntaxException, TransportException
+          throws NotSupportedException, URISyntaxException, TransportException,
+                 RepositoryClientException
+  {
+    FetchResult r = null;
+
+    try
     {
       Transport tn = Transport.open(repository, Constants.HEAD);
 
@@ -396,8 +407,6 @@ public class GitRepositoryClient implements RepositoryClient
         tn.setCredentialsProvider(credentialsProvider);
       }
 
-    FetchResult r;
-
       try
       {
         r = tn.fetch(new TextProgressMonitor(), null);
@@ -406,6 +415,13 @@ public class GitRepositoryClient implements RepositoryClient
       {
         tn.close();
       }
+    }
+    catch (NoRemoteRepositoryException ex)
+    {
+
+      // empty repository, call init
+      init();
+    }
 
     return r;
   }