Opportunistic cleanup

Both these members are always null. If iface is non-null, this
condition is false. If iface is null, then sourceAddrs can't
be null else NPE, but if it's not null it's not equals(null)
so this condition is necessarily always false.

Bug: None
Test: FrameworksTestsNet NetworkStackTests
Change-Id: Iedda059e516f1816edfe942790bc3c42d78fe748