Ignore some folders from doctest scanning (#1465)
Ignore some folders from doctest scanning (#1465)

* remove movielens downloading from unittest

* fix spark1.5 Lock problem

* fix return

intel-analytics/BigDL,yangw1234/BigDL,intel-analytics/BigDL,intel-analytics/BigDL,yangw1234/BigDL,yangw1234/BigDL,intel-analytics/BigDL,yangw1234/BigDL