Avoid NPE if icon assignment failed for whatever reason.

Change-Id: Iba4188d6b42179008154b8cbcbb14c36a22669de
Fix adding lockscreen targets.

The empty targets were not included in the setting properly.
Also make the code a little more memory efficient.

Change-Id: I05cc7ce55ef5789f063033116ebfd9337e5ee28a
Lockscreen targets: more unification

Use shared method to derive drawable inset and make the rounded
corners for icon files also display when adding the target initially.

Change-Id: I98ea3e522c4c6240f08e11007d53509a3d2c15f8
Fix drawable being displayed empty when re-entering the target edit
dialog.

Change-Id: I032a8d8b348803448365ed81246c556da6ff4cc4