gnu: Reference the inherited inputs values.

This commit was made by running this command:

  sed -e's/modify-inputs (package-\([a-z-]*\)inputs [a-zA-Z0-9-]\+)/modify-inputs \1inputs/g' -i gnu/packages/*.scm

… and then reverting individual hunks where the change would trigger unbound
variable warnings or other issues (such as ‘native-inputs’ is bound in the
body of the ‘inputs’ field, but it refers to the ‘native-inputs’ thunk defined
just above).

Change-Id: I6d94819f2809313fa1fbefc61897502ee7d66fab

gnu/packages/bittorrent.scm

@@ -597,7 +597,7 @@ features.")
          ((#:configure-flags configure-flags)
           #~(cons "-DGUI=OFF" #$configure-flags))))
       (inputs
-       (modify-inputs (package-inputs base)
+       (modify-inputs inputs
          (delete "qtsvg"))))))
 
 (define-deprecated-package qbittorrent-nox