Initialise ReceiveCommand status to NOT_ATTEMPTED for all constructors

Formerly the 4-arg constructor did not do this, which was unfortunate
as that constructor's the only way for an external user of JGit to set
the /type/ of the ref-update - which you might want to do to indicate
that the update is expected to be a UPDATE_NONFASTFORWARD, and thus does
not require expensive isMergedInto() calculations:

http://dev.eclipse.org/mhonarc/lists/jgit-dev/msg02258.html

Change-Id: I84c5e4927131e105bed93e31a62da6367c78de32
Signed-off-by: Roberto Tyley <roberto.tyley@gmail.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/RefDirectoryTest.java

@@ -1278,10 +1278,8 @@ public class RefDirectoryTest extends LocalDiskRepositoryTestCase {
 
 	private static ReceiveCommand newCommand(RevCommit a, RevCommit b,
 			String string, Type update) {
-		ReceiveCommand ret = new ReceiveCommand(a != null ? a.getId() : null,
+		return new ReceiveCommand(a != null ? a.getId() : null,
 				b != null ? b.getId() : null, string, update);
-		ret.setResult(ReceiveCommand.Result.NOT_ATTEMPTED);
-		return ret;
 	}
 
 	private void writeLooseRef(String name, AnyObjectId id) throws IOException {

org.eclipse.jgit/src/org/eclipse/jgit/transport/ReceiveCommand.java

@@ -157,7 +157,7 @@ public class ReceiveCommand {
 
 	private Ref ref;
 
-	private Result status;
+	private Result status = Result.NOT_ATTEMPTED;
 
 	private String message;
 
@@ -186,7 +186,6 @@ public class ReceiveCommand {
 			type = Type.CREATE;
 		if (ObjectId.zeroId().equals(newId))
 			type = Type.DELETE;
-		status = Result.NOT_ATTEMPTED;
 	}
 
 	/**