Fix bug : FeedHive scheduled update isn't complete sometimes.

Here is my hypothesis.
- scheduled update is started. And it takes long~ time.
- system doesn't have enough memory and LMK triggered.
- LMK kills feedhive. So, update isn't complete and icon isn't removed.

Here is fix.
- update and download notification icon is integrated into 'action' noti.
- whenever 'download' or 'update' action is started, LifeSupportService is set
    as foreground (to keep from LMK.)

TODO: enough test is required.