ListObjects: IsTruncated omit when its value is false

[mars4myshare]

Issue

When listObjects, if the number of objects is less than the 'MaxKeys', there is no 'IsTruncated' field

Detail

There were two objects in the bucket. Here is the return of listObjects

{
  Contents: [{
      ETag: "\"d084225e6144cafa320aa8454349094d\"",
      Key: "test1.txt",
      LastModified: 2019-12-26 08:11:40.466 +0000 UTC,
      Size: 56
    },{
      ETag: "\"d084225e6144cafa320aa8454349094d\"",
      Key: "test2.txt",
      LastModified: 2019-12-26 08:11:40.467 +0000 UTC,
      Size: 56
    }],
  Marker: "",
  MaxKeys: 3,
  Name: "newbucket",
  Prefix: ""
}

Expected return:

{
  Contents: [{
      ETag: "\"d084225e6144cafa320aa8454349094d\"",
      Key: "test1.txt",
      LastModified: 2019-12-26 08:44:01.079 +0000 UTC,
      Size: 56
    },{
      ETag: "\"d084225e6144cafa320aa8454349094d\"",
      Key: "test2.txt",
      LastModified: 2019-12-26 08:44:01.079 +0000 UTC,
      Size: 56
    }],
  IsTruncated: false,
  Marker: "",
  MaxKeys: 3,
  Name: "newbucket",
  Prefix: ""
}

[mars4myshare]

Fixed with #39

Now the return is

{
  Contents: [{
      ETag: "\"d084225e6144cafa320aa8454349094d\"",
      Key: "test1.txt",
      LastModified: 2019-12-26 08:44:01.079 +0000 UTC,
      Size: 56
    },{
      ETag: "\"d084225e6144cafa320aa8454349094d\"",
      Key: "test2.txt",
      LastModified: 2019-12-26 08:44:01.079 +0000 UTC,
      Size: 56
    }],
  IsTruncated: false,
  Marker: "",
  MaxKeys: 3,
  Name: "newbucket",
  Prefix: ""
}

[johannesboyne]

(s.a. fixed with #39 - merged)