When using a datagrid that consists of both TH and TD cells in a row,

content alignment would begin to fail. This is due to some inherited

browser styles for vertical alignment on TH, and different padding

definitions between TH and TD.
We now set the alignment and padding on both of these at the same time,

ensuring they line up.

Tested all the typical datagrids in Review Board, plus the admin UI

datagrids, ensuring that alignment was always correct.