xenconfig: channels conversion support
    
    Add support for formating/parsing libxl channels.
    
    Syntax on xen libxl goes as following:
    channel=["connection=pty|socket,path=/path/to/socket,name=XXX",...]
    
    Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
    Acked-by: Jim Fehlig <jfehlig@suse.com>
    Signed-off-by: Jim Fehlig <jfehlig@suse.com>