Add profile_id parameter to 'request_certificate'
    
    Add the profile_id parameter to the 'request_certificate' function
    and update call sites.
    
    Also remove multiple occurrences of the default profile ID
    'caIPAserviceCert'.
    
    Part of: https://fedorahosted.org/freeipa/ticket/57
    
    Reviewed-By: Martin Basti <mbasti@redhat.com>