gnu: ardour: Fix inheritance of Ardour package.

* gnu/packages/audio.scm (ardour): Inherit from "ardour-3" instead of
  "ardour".

gnu/packages/audio.scm

@@ -226,7 +226,7 @@ (define-public ardour-3
     (license license:gpl2+)))
 
 (define-public ardour
-  (package (inherit ardour)
+  (package (inherit ardour-3)
     (name "ardour")
     (version "4.0")
     (source (origin