Reset preferred APN setting after restoring default APNs

After reset of APN DB, the APNs might not be changed, but its APN
ID is changed, so that the connected APN is not seleted from UI.

To fix it, reset preferred APN with the same APN added newly.

Change-Id: I8ef2dc8268fb22d6703a191b7db51f876ddbfabe
CRs-Fixed: 2362190