download: Refer to the 'guile-gnutls' package and not 'gnutls'.

This reinstates c625e5b64d, which was
reverted due to a circular dependency:

  https://issues.guix.gnu.org/63331

This is a followup to 305794762c, which
removed Guile bindings from 'gnutls'.

* guix/android-repo-download.scm (android-repo-fetch): Refer to
'guile-gnutls instead of 'gnutls.
* guix/cvs-download.scm (cvs-fetch): Likewise.
* guix/git-download.scm (git-fetch): Likewise.
* guix/hg-download.scm (hg-fetch): Likewise.

guix/android-repo-download.scm

@@ -82,7 +82,7 @@ generic name if unset."
     (module-ref (resolve-interface '(gnu packages guile)) 'guile-lzlib))
 
   (define gnutls
-    (module-ref (resolve-interface '(gnu packages tls)) 'gnutls))
+    (module-ref (resolve-interface '(gnu packages tls)) 'guile-gnutls))
 
   (define config.scm
     (scheme-file "config.scm"

guix/cvs-download.scm

@@ -68,7 +68,7 @@ HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
     (module-ref (resolve-interface '(gnu packages guile)) 'guile-json-4))
 
   (define gnutls
-    (module-ref (resolve-interface '(gnu packages tls)) 'gnutls))
+    (module-ref (resolve-interface '(gnu packages tls)) 'guile-gnutls))
 
   (define modules
     (delete '(guix config)

guix/git-download.scm

@@ -105,7 +105,7 @@ HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
     (module-ref (resolve-interface '(gnu packages guile)) 'guile-lzlib))
 
   (define gnutls
-    (module-ref (resolve-interface '(gnu packages tls)) 'gnutls))
+    (module-ref (resolve-interface '(gnu packages tls)) 'guile-gnutls))
 
   (define glibc-locales
     ;; Note: pick the '-final' variant to avoid circular dependency on

guix/hg-download.scm

@@ -79,7 +79,7 @@ HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
     (module-ref (resolve-interface '(gnu packages guile)) 'guile-json-4))
 
   (define gnutls
-    (module-ref (resolve-interface '(gnu packages tls)) 'gnutls))
+    (module-ref (resolve-interface '(gnu packages tls)) 'guile-gnutls))
 
   (define modules
     (delete '(guix config)