RowsFragment: use default alignment if setAlignment() not called

Some apps expects default alignment, a regression in support lib
25 will make RowsFragment rows to align to top of screen by default.

Bug 33279341
Test RowsFragmentTest RowsSupportFragmentTest

Change-Id: I2a8c78ac1c40fe6c0b12b624ab99bb6ced06a8ee
12 files changed