system.prop: remove default network build property.

Not needed and is not present in CM10/jellybean branch

Change-Id: I0c245223bd9ac55c40c923536587fb31d9d322ad
system.prop: bring back scrolling tweaks.

Since we switched back to our original display hals this seems to do some
good again

Plus minor cleanup

Change-Id: I0ea0254e428243e1fa154c1e18b7d0f27f9f58a5