sssctl: Search by alias
    
    Also search by alias when using sssctl to query the cache.
    
    Resolves:
    https://fedorahosted.org/sssd/ticket/3235
    
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
    (cherry picked from commit d6e875c49d6be650a03fc14f00a680734b23ef66)