system: Make service procedures non-monadic.

* gnu/services/avahi.scm (configuration-file): Use 'plain-file' instead
  of 'text-file'.
  (avahi-service): Turn into a regular procedure that returns a <service>.
* gnu/services/base.scm (root-file-system-service, file-system-service,
  user-unmount-service, user-processes-service, host-name-service,
  console-keymap-service, console-font-service, mingetty-service,
  nscd.conf-file, nscd-service): Likewise.
  (%default-syslog.conf): New variable.
  (syslog-service): Use it.  Turn into a regular procedure.
  (guix-service, udev-rules-union, kvm-udev-rule, udev-service,
  device-mapping-service, swap-service): Likewise.
* gnu/services/databases.scm (%default-postgres-hba,
  %default-postgres-ident): Use 'plain-file' instead of 'text-file'.
  (%default-postgres-config): Use 'mixed-text-file' instead of
  'text-file*'.
  (postgresql-service):  Use 'program-file' instead of 'gexp->script'.
  Turn into a regular procedure.
* gnu/services/desktop.scm (dbus-configuration-directory): Use
  'computed-file' instead of 'gexp->derivation'.
  (upower-configuration-file, geoclue-configuration-file,
  elogind-configuration-file): Use 'plain-file' instead of 'text-file'.
  (dbus-service, upower-service, colord-service, geoclue-service,
  polkit-service, elogind-service): Turn into regular procedures.
  (%desktop-services): Remove use of 'mlet' when iterating on
  %BASE-SERVICES.
* gnu/services/lirc.scm (lirc-service): Turn into a regular procedure.
* gnu/services/networking.scm (static-networking-service,
  dhcp-client-service, ntp-service, tor-service, bitlbee-service,
  wicd-service): Likewise.
* gnu/services/ssh.scm (lsh-service): Likewise.
* gnu/services/web.scm (nginx-service): Likewise.
* gnu/services/xorg.scm (xorg-configuration-file): Use 'mixed-text-file'
  instead of 'text-file*'.
  (xorg-start-command, slim-service): Turn into regular procedures.
  (xinitrc): Use 'program-file' instead of 'gexp->script'.
* gnu/system/install.scm (cow-store-service,
  configuration-template-service): Turn into regular procedures.
* gnu/system.scm (other-file-system-services, device-mapping-services,
  swap-services, essential-services, operating-system-services,
  user-shells, operating-system-accounts): Remove now unnecessary
  'mlet' and turn into regular procedures.
  (operating-system-etc-directory, operating-system-activation-script,
  operating-system-boot-script): Adjust accordingly.
* doc/guix.texi (Base Services, Networking Services, X Window, Desktop
  Services, Database Services, Web Services, Various Services, Name
  Service Switch): Adjust accordingly.

gnu/services/ssh.scm

@@ -19,7 +19,6 @@
 (define-module (gnu services ssh)
   #:use-module (guix gexp)
   #:use-module (guix store)
-  #:use-module (guix monads)
   #:use-module (gnu services)
   #:use-module (gnu system linux)                 ; 'pam-service'
   #:use-module (gnu packages lsh)
@@ -152,22 +151,21 @@ The other options should be self-descriptive."
         '(networking syslogd)
         '(networking)))
 
-  (with-monad %store-monad
-    (return (service
-             (documentation "GNU lsh SSH server")
-             (provision '(ssh-daemon))
-             (requirement requires)
-             (start #~(make-forkexec-constructor (list #$@lsh-command)))
-             (stop  #~(make-kill-destructor))
-             (pam-services
-              (list (unix-pam-service
-                     "lshd"
-                     #:allow-empty-passwords? allow-empty-passwords?)))
-             (activate #~(begin
-                           (use-modules (guix build utils))
-                           (mkdir-p "/var/spool/lsh")
-                           #$(if initialize?
-                                 (activation lsh host-key)
-                                 #t)))))))
+  (service
+   (documentation "GNU lsh SSH server")
+   (provision '(ssh-daemon))
+   (requirement requires)
+   (start #~(make-forkexec-constructor (list #$@lsh-command)))
+   (stop  #~(make-kill-destructor))
+   (pam-services
+    (list (unix-pam-service
+           "lshd"
+           #:allow-empty-passwords? allow-empty-passwords?)))
+   (activate #~(begin
+                 (use-modules (guix build utils))
+                 (mkdir-p "/var/spool/lsh")
+                 #$(if initialize?
+                       (activation lsh host-key)
+                       #t)))))
 
 ;;; ssh.scm ends here