Should not suspend to RAM when closing lid on battery power

Originally created by @matsa on #8071 (Redmine)

Closing the screen now suspends to RAM, which brings the following problems:

- the emergency shutdown is broken: removing the device does not shut down and erase the memory.
- When closing the screen and reopen it directly, Tails (sometime) freezes.

BTW, there is no obvious way to change this setting in Tails Wheezy.

Feature Branch: matsa:bugfix/8071-Do-not-suspend-to-RAM-when-closing-lid

Related issues

Related to #11052 (closed)

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