Revert "Mobile QML UI: fix more background colors (gpslist)"

This worked correctly while compiled against Qt 5.10.0, but after
installing Qt 5.10.1 the behavior was just wrong. And as there
seems no way to color the background of a Kirigami SwipeListItem,
just revert this, and accept the (slightly) inconsistent coloring
of the page (for now).

This reverts commit 6700715b5dc1d314bc73800d8f8ec387d4d20d16.

Signed-off-by: Jan Mulder <jlmulder@xs4all.nl>

mobile-widgets/qml/GpsList.qml

@@ -20,10 +20,6 @@ Kirigami.ScrollablePage {
 			id: gpsFix
 			enabled: true
 			width: parent.width
-			background: Rectangle {
-				color: subsurfaceTheme.backgroundColor
-				border.width: 1
-			}
 			GridLayout {
 				columns: 4
 				id: timeAndName