Build: merge ipatests/man/configure.ac to top-level configure.ac
    
    At the same time, I removed unnecessary checks for mkdir etc. and added
    missing check for gzip.
    
    https://fedorahosted.org/freeipa/ticket/6418
    
    Reviewed-By: Lukas Slebodnik <lslebodn@redhat.com>
    Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>