Improve handling of command line parameters, don't silently ignore unexpected arguments.
Improve handling of command line parameters, don't silently ignore unexpected arguments.

This is to avoid following behavior:

    [abb@dom0 qubes-core]$ qvm-block -l
    netvm:sda       STORAGE_DEVICE () 0 B
    dom0:sdb1       Cruzer () 3 GiB
    dom0:sdb        Cruzer () 3 GiB

    [abb@dom0 qubes-core]$ qvm-block -l
    netvm:sda       STORAGE_DEVICE () 0 B
    dom0:sdb1       Cruzer () 3 GiB
    dom0:sdb        Cruzer () 3 GiB

    [abb@dom0 qubes-core]$ qvm-block -a qdvp dom0:sdb

    [abb@dom0 qubes-core]$ qvm-block -l
    netvm:sda       STORAGE_DEVICE () 0 B
    dom0:sdb1       Cruzer () 3 GiB
    dom0:sdb        Cruzer () 3 GiB (attached to 'qdvp' as 'xvdi')

    [abb@dom0 qubes-core]$ qvm-block -d qdvp BLAHBLAH
                                          ^^^^^^^^^^^^^
    >>> The last parameter is silently ignored and all devices get detached

    [abb@dom0 qubes-core]$ qvm-block -l
    netvm:sda       STORAGE_DEVICE () 0 B
    dom0:sdb1       Cruzer () 3 GiB
    dom0:sdb        Cruzer () 3 GiB

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