System Information
Xbuntu / AMD

Blender Version
ee9d375

Short description of error
No matter what you are doing the number for users for action datablock goes up.

Exact steps for others to reproduce the error
New file
Have a 3d viewport and the action editor open
Select the cube and set a keyframe (this will create a new action datablock for the cube)
Now rotate/move/scale/whatever the cube and look at the number of users using this action datablock
...however if you hit undo (Ctrl+Z) then the number goes back down to what it should be...