etc: Remove hydra.gnu.org.pub key.

* etc/substitutes/hydra.gnu.org.pub: Delete file.
* guix/self.scm (miscellaneous-files): Don't install it.
* Makefile.am (dist_pkgdata_DATA): Remove it.
* gnu/services/base.scm (%default-authorized-guix-keys): Likewise.
(hydra-key-authorization): Rename to…
(substitute-key-authorization): …this.  Adjust only call site.

Makefile.am

@@ -489,9 +489,8 @@ check-system: $(GOBJECTS)
 	   -e '(@@ (run-system-tests) run-system-tests)'	\
 	   $(top_srcdir)/build-aux/run-system-tests.scm
 
-# Public key used to sign substitutes from hydra.gnu.org & co.
+# Public keys used to sign substitutes.
 dist_pkgdata_DATA =				\
-  etc/substitutes/hydra.gnu.org.pub		\
   etc/substitutes/berlin.guixsd.org.pub		\
   etc/substitutes/ci.guix.gnu.org.pub		\
   etc/substitutes/ci.guix.info.pub

etc/substitutes/hydra.gnu.org.pub

@@ -1,6 +0,0 @@
- (public-key 
-  (rsa 
-   (n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
-   (e #010001#)
-   )
-  )

gnu/services/base.scm

@@ -1533,7 +1533,7 @@ GID."
     (('gnu rest ...) #t)
     (rest #f)))
 
-(define (hydra-key-authorization keys guix)
+(define (substitute-key-authorization keys guix)
   "Return a gexp with code to register KEYS, a list of files containing 'guix
 archive' public keys, with GUIX."
   (define default-acl
@@ -1570,8 +1570,7 @@ archive' public keys, with GUIX."
 
 (define %default-authorized-guix-keys
   ;; List of authorized substitute keys.
-  (list (file-append guix "/share/guix/hydra.gnu.org.pub")
-        (file-append guix "/share/guix/berlin.guixsd.org.pub")))
+  (list (file-append guix "/share/guix/berlin.guixsd.org.pub")))
 
 (define-record-type* <guix-configuration>
   guix-configuration make-guix-configuration
@@ -1688,7 +1687,7 @@ archive' public keys, with GUIX."
 
      ;; Optionally authorize substitute server keys.
      (if authorize-key?
-         (hydra-key-authorization keys guix)
+         (substitute-key-authorization keys guix)
          #~#f))))
 
 (define* (references-file item #:optional (name "references"))

gnu/system/install.scm

@@ -330,8 +330,8 @@ Access documentation at any time by pressing Alt-F2.\x1b[0m
           ;; The usual services.
           (syslog-service)
 
-          ;; The build daemon.  Register the hydra.gnu.org key as trusted.
-          ;; This allows the installation process to use substitutes by
+          ;; The build daemon.  Register the default substitute server key(s)
+          ;; as trusted to allow the installation process to use substitutes by
           ;; default.
           (service guix-service-type
                    (guix-configuration (authorize-key? #t)))

guix/self.scm

@@ -577,9 +577,6 @@ load path."
                    ,(file-append* source "/etc/completion/zsh/_guix"))
                   ("share/fish/vendor_completions.d/guix.fish"
                    ,(file-append* source "/etc/completion/fish/guix.fish"))
-                  ("share/guix/hydra.gnu.org.pub"
-                   ,(file-append* source
-                                  "/etc/substitutes/hydra.gnu.org.pub"))
                   ("share/guix/berlin.guixsd.org.pub"
                    ,(file-append* source
                                   "/etc/substitutes/berlin.guixsd.org.pub"))