Doc: update hadoop document. (#5623)
Doc: update hadoop document. (#5623)

* doc: update hadoop document.

* fix: fix wording.

* fix: fix wording.

* fix: fix wording.
intel-analytics/BigDL,intel-analytics/BigDL,yangw1234/BigDL,intel-analytics/BigDL,intel-analytics/BigDL,yangw1234/BigDL,yangw1234/BigDL,yangw1234/BigDL