Fix bugs in qvm-shutdown --all
Fix bugs in qvm-shutdown --all

- Exit the program if all domains are halted
- Changed log.notice to log.info
- Replace map with dictionary comprehensions (pylint)

QubesOS/qubes-core-admin,marmarek/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin