Work around RPM caret bug when checking advisory packages
    
    There's a bug in rpm where doing `rpm -q [NVRA]` doesn't work
    if the NVRA contains a caret. To make it work you have to add
    a literal slash character before the caret character, so we add
    a sed command to do that, when we're checking whether packages
    from the update actually got installed.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>