bug#66290: transmission-daemon-service-type not serving web interface

[elaexuotee]

The documentation for transmission-daemon-service-type makes it sound like the
web interface should be up and running:

       Once the service is started, users can interact with the daemon
    through its Web interface (at ‘http://localhost:9091/’) ...

However, the daemon throws 404 when accessing said url:

    404: Not Found

    Couldn't find Transmission's web interface files!

    Users: to tell Transmission where to look, set the TRANSMISSION_WEB_HOME 
environment variable to the folder where the web interface's index.html is 
located.

    Package Builders: to set a custom default at compile time, #define 
PACKAGE_DATA_DIR in libtransmission/platform.c or tweak tr_getClutchDir() by 
hand.

Anyone else seeing this?

Just for good measure, here is my config:

    (transmission-daemon-configuration
      (rpc-authentication-required? #t)
      (rpc-username "transmission")
      (rpc-password "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")
      (rpc-whitelist-enabled? #t)
      (rpc-whitelist          '("::1" "127.0.0.1" "192.168.*"))
      (encryption 'require-encrypted-connections)
      (alt-speed-down (* 1024 1)) ; 1MB/s
      (alt-speed-up   512)
      (alt-speed-time-enabled? #t)
      (alt-speed-time-day      'weekdays)
      (alt-speed-time-begin    (* 60 8))
      (alt-speed-time-end      (* 60 19))
      (watch-dir-enabled? #t)
      (watch-dir          "/var/lib/transmission-daemon/torrents"))