restart networkmanager on suspend resume
nixos-install: fix error message consistency

The test is for path A but the error message says path B. Fix it.
Merge pull request #149 from NixOS/networkmanager_suspend

restart networkmanager on suspend resume
Merge pull request #150 from bjornfor/nixos-install-fix-errormsg

nixos-install: fix error message consistency
Removing unneded imports for the display-manager.

Discussed in
https://github.com/NixOS/nixos/commit/2e088aa2779a91b787a44fd9e3f44a9ef2f2edd9#commitcomment-3074283
atd: add "batch" to the list of programs that need a setuid wrapper