Always use /etc/ipa/ca.crt as CA cert file
    
    It seem like ALIAS_CACERT_ASC was just a redundant location for the CA
    cert file which is always available in /etc/ipa/ca.crt
    
    Just use the canonical CA cert location in /etc/ipa for all cases and
    stop creating a separate cacert file.
    
    https://fedorahosted.org/freeipa/ticket/5959
    
    Signed-off-by: Simo Sorce <simo@redhat.com>
    Reviewed-By: Jan Cholasta <jcholast@redhat.com>