Use the full versions of the message, instead of composing a base
message with what was updated; the change makes the messages properly
translatable, since different parts of a sentence might need different
declensions for example.
Turn various vshPrint() informative messages into vshPrintExtra(), so
they are not printed when requesting the quiet mode; neither XML/info
outputs nor the results of commands are affected.
Also change the expected outputs of the virsh-undefine test, since virsh
is invoked in quiet mode there.
Some informative messages might still be converted (and thus silenced
when in quiet mode), but this is an improvements nonetheless.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1358179