Convert set*Quota to use iptablesRestore.

Bug: 28362720
Test: bullhead builds,boots
Test: netd_{unit,integration}_test pass
Test: quota rules are added and removed when quotas are enabled/disabled
Change-Id: Ib4df4f10a26c8bc206cc67671da09618fa4224ac
Merged-In: I2b68d17d7c7640e3956ae010f9882d34bf24d9fc