Deleting wifi certificates isn't supported yet since cascading the
removal back into wifi configs will need some easy way of enumerating
wifi configs first.
Bug: 29208062
Change-Id: I2d9d1ea7e0974701009bfa6ea162b8bc80806639
This makes removing a particular keyset possible without deleting the
whole keystore along with it.
Bug: 22541933
Change-Id: I248803cb27efdd1695438dfc82951887dc579f99