SystemUI: new drawables to fix signal bar color when data is off
Thanks to @szlkiev

Change-Id: I58b8177271607249fc787fb21d10c9091e66e15e

Conflicts:
	packages/SystemUI/res/drawable-hdpi/stat_sys_signal_0.png
	packages/SystemUI/res/drawable-hdpi/stat_sys_signal_1.png
	packages/SystemUI/res/drawable-hdpi/stat_sys_signal_2.png
	packages/SystemUI/res/drawable-hdpi/stat_sys_signal_3.png
	packages/SystemUI/res/drawable-hdpi/stat_sys_signal_4.png
	packages/SystemUI/res/drawable-sw1000dp-xhdpi/stat_sys_signal_0.png
	packages/SystemUI/res/drawable-sw1000dp-xhdpi/stat_sys_signal_1.png
	packages/SystemUI/res/drawable-sw1000dp-xhdpi/stat_sys_signal_2.png
	packages/SystemUI/res/drawable-sw1000dp-xhdpi/stat_sys_signal_3.png
	packages/SystemUI/res/drawable-sw1000dp-xhdpi/stat_sys_signal_4.png
	packages/SystemUI/res/drawable-xhdpi/stat_sys_signal_0.png
	packages/SystemUI/res/drawable-xhdpi/stat_sys_signal_1.png
	packages/SystemUI/res/drawable-xhdpi/stat_sys_signal_2.png
	packages/SystemUI/res/drawable-xhdpi/stat_sys_signal_3.png
	packages/SystemUI/res/drawable-xhdpi/stat_sys_signal_4.png