Settings: modify AOSP RU translation

Changed "data_usage_menu_metered" and "data_usage_metered_title" to
state it configures Mobile hotspots, not something like APNs.

Change-Id: I40db1da7d6f4a801de5a06c6a5790580da080ebd
settings: Remove "mobile plan"

 * Useless menu item.

Change-Id: I0b35017cb9a52600cde5d31065f007210f916a41