Fix API ListBranchCommand for listmode 'all'

If remote branches are present they can not be added
to the RefMap from the local branches - the two RefMaps
have a different value of 'prefix' and consequently an
IllegalArgumentException is thrown.

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/BranchCommandTest.java

@@ -189,6 +189,12 @@ public class BranchCommandTest extends RepositoryTestCase {
 				- allBefore);
 	}
 
+	@Test
+	public void testListAllBranchesShouldNotDie() throws Exception {
+		Git git = setUpRepoWithRemote();
+		git.branchList().setListMode(ListMode.ALL).call();
+	}
+
 	@Test
 	public void testCreateFromCommit() throws Exception {
 		Ref branch = git.branchCreate().setName("FromInitial").setStartPoint(

org.eclipse.jgit/src/org/eclipse/jgit/api/ListBranchCommand.java

@@ -49,6 +49,7 @@ import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
+import java.util.HashMap;
 
 import org.eclipse.jgit.api.errors.JGitInternalException;
 import org.eclipse.jgit.lib.Constants;
@@ -100,7 +101,8 @@ public class ListBranchCommand extends GitCommand<List<Ref>> {
 			} else if (listMode == ListMode.REMOTE) {
 				refList = repo.getRefDatabase().getRefs(Constants.R_REMOTES);
 			} else {
-				refList = repo.getRefDatabase().getRefs(Constants.R_HEADS);
+				refList = new HashMap<String,Ref>(repo.getRefDatabase().getRefs(
+						Constants.R_HEADS));
 				refList.putAll(repo.getRefDatabase().getRefs(
 						Constants.R_REMOTES));
 			}