SystemUI:Notification bar custom notification display problems

Install souhuxinwen.apk,5.8.4, Push the information of the
status bar shows black background + black font.
When apk's targetSdk<19 notification background will be set
to black color(#ff1a1a1a),so change the color to NormalColor
(#ffffffff) to match the display.

Change-Id: I58883e04b174f2b0dd3e00b2fadaf287de41bbb2
CRs-Fixed: 2004506