[FIX][MLLIB] fix seed in BaggedPointSuite

Saw Jenkins test failures due to random seeds.

jkbradley manishamde

Author: Xiangrui Meng <meng@databricks.com>

Closes #3084 from mengxr/fix-baggedpoint-suite and squashes the following commits:

f735a43 [Xiangrui Meng] fix seed in BaggedPointSuite

(cherry picked from commit c5912ecc7b392a13089ae735c07c2d7256de36c6)
Signed-off-by: Xiangrui Meng <meng@databricks.com>