gnu: libechonest: Remove package.

It appears the "EchoNest" service isn't available anymore which makes this
package obsolete.

* gnu/packages/music.scm (libechonest): Remove variable.
(clementine)[inputs]: Remove libechonest.

Signed-off-by: Efraim Flashner <efraim@flashner.co.il>

gnu/packages/music.scm

@@ -262,7 +262,6 @@ score, keyboard, guitar, drum and controller views.")
          ("gst-plugins-base" ,gst-plugins-base)
          ("libcdio" ,libcdio)
          ("libmygpo-qt" ,libmygpo-qt)
-         ("libechonest" ,libechonest)
          ;; TODO: Package libgpod.
          ("libmtp" ,libmtp)
          ("libxml2" ,libxml2)
@@ -3809,33 +3808,6 @@ OSC connections.")
 the electronic or dubstep genre.")
     (license license:gpl3+)))
 
-(define-public libechonest
-  (package
-    (name "libechonest")
-    (version "2.3.1")
-    (source (origin
-              (method git-fetch)
-              (uri (git-reference
-                    (url "git://anongit.kde.org/libechonest.git")
-                    (commit version)))
-              (file-name (string-append name "-" version "-checkout"))
-              (sha256
-               (base32
-                "0xbavf9f355dl1d3qv59x4ryypqrdanh9xdvw2d0q66l008crdkq"))))
-    (build-system cmake-build-system)
-    (arguments
-     '(#:tests? #f                      ; Tests require Internet access
-       #:configure-flags '("-DBUILD_WITH_QT4=OFF")))
-    (inputs
-     `(("qtbase" ,qtbase)
-       ("qjson" ,qjson)))
-    (home-page "https://projects.kde.org/projects/playground/libs/libechonest")
-    (synopsis "C++/Qt classes to interface with The Echo Nest API")
-    (description "@code{libechonest} is a collection of C++/Qt classes
-designed to make a developer's life easy when trying to use the APIs provided
-by The Echo Nest.")
-    (license license:gpl2+)))
-
 (define-public libmygpo-qt
   (package
     (name "libmygpo-qt")