core,webadmin: show list of changed fields when updating running vm

When updating running vm, a msg is shown if some of the fields can be
updated only after restart.

This is changed to list those fields for the user.

Change-Id: Idf13a19d1b193037226cb49bc6c1e8cefc0553b8
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1119791
Signed-off-by: Omer Frenkel <ofrenkel@redhat.com>