services: tor: Do not write to /var/log/tor.log.

The service uses syslog and additionally shepherd 0.9 captures its
stdout/stderr, so there's no point in passing #:log-file.

* gnu/services/networking.scm (tor-shepherd-service): Remove #:log-file
argument to 'make-forkexec-constructor'.
(%tor-log-rotation): Remove.
(tor-service-type): Remove ROTTLOG-SERVICE-TYPE extension.

gnu/services/networking.scm

@@ -997,15 +997,10 @@ (define (tor-shepherd-service config)
                 ;; 'sd_notify' though), so we're stuck with that.
                 (start #~(make-forkexec-constructor
                           (list #$tor "-f" #$torrc)
-                          #:user "tor" #:group "tor"
-                          #:log-file "/var/log/tor.log"))
+                          #:user "tor" #:group "tor"))
                 (stop #~(make-kill-destructor))
                 (documentation "Run the Tor anonymous network overlay."))))))))
 
-(define %tor-log-rotation
-  (list (log-rotation
-         (files '("/var/log/tor.log")))))
-
 (define (tor-activation config)
   "Set up directories for Tor and its hidden services, if any."
   #~(begin
@@ -1051,9 +1046,7 @@ (define tor-service-type
                        (service-extension account-service-type
                                           (const %tor-accounts))
                        (service-extension activation-service-type
-                                          tor-activation)
-                       (service-extension rottlog-service-type
-                                          (const %tor-log-rotation))))
+                                          tor-activation)))
 
                 ;; This can be extended with hidden services.
                 (compose concatenate)