Changes to the mta policy module and relevant dependencies
    
    Ported from Fedora with changes
    
    Do not allow the mta_role callers role the mta_user_agent attribute
    
    If they run it they need to call they domains run interface like exim
    does in mta_role
    
    Only exim seems to be a working mta_user_agent
    
    Domains like qmail_inject_t, qmail_queue_t and postfix_postdrop_t
    are classified mta_user_agent but there is no domain transition from
    the user domains to those mta_user_agent domains
    
    The qmail inject and queue executable file arent classified
    mta_user_agent_executable file either
    
    Signed-off-by: Dominick Grift <dominick.grift@gmail.com>