Tramp code cleanup

* lisp/net/tramp-cache.el (tramp-get-connection-property): Cleanup.

* lisp/net/tramp-cmds.el (tramp-cleanup-all-connections): Delete also
connection processes.

* lisp/net/tramp-sh.el (tramp-set-remote-path): Cache 4096 even if
PIPE_BUF doesn't exist.

lisp/net/tramp-cache.el

@@ -142,7 +142,7 @@ Return DEFAULT if not set."
 	 (cached (and (hash-table-p hash) (gethash property hash)))
 	 (cached-at (and (consp cached) (format-time-string "%T" (car cached))))
 	 (value default)
-	 use-cache)
+	 cache-used)
 
     (when ;; We take the value only if there is any, and
 	  ;; `remote-file-name-inhibit-cache' indicates that it is
@@ -157,11 +157,11 @@ Return DEFAULT if not set."
 		      (time-less-p
 		       remote-file-name-inhibit-cache (car cached)))))
       (setq value (cdr cached)
-	    use-cache t))
+	    cache-used t))
 
-    (tramp-message key 8 "%s %s %s; inhibit: %s; cache used: %s; cached at: %s"
-                   file property value
-		   remote-file-name-inhibit-cache use-cache cached-at)
+    (tramp-message
+     key 8 "%s %s %s; inhibit: %s; cache used: %s; cached at: %s"
+     file property value remote-file-name-inhibit-cache cache-used cached-at)
     (when (>= tramp-verbose 10)
       (let* ((var (intern (concat "tramp-cache-get-count-" property)))
 	     (val (or (numberp (bound-and-true-p var))
@@ -320,15 +320,15 @@ the connection, return DEFAULT."
 		     (gethash property hash tramp-cache-undefined)
 		   tramp-cache-undefined))
 	 (value default)
-	 use-cache)
+	 cache-used)
 
     (when (and (not (eq cached tramp-cache-undefined))
 	       ;; If the key is an auxiliary process object, check
 	       ;; whether the process is still alive.
 	       (not (and (processp key) (not (process-live-p key)))))
       (setq value cached
-	    use-cache t))
-    (tramp-message key 7 "%s %s; cache used: %s" property value use-cache)
+	    cache-used t))
+    (tramp-message key 7 "%s %s; cache used: %s" property value cache-used)
     value))
 
 ;;;###tramp-autoload

lisp/net/tramp-cmds.el

@@ -184,8 +184,9 @@ This includes password cache, file cache, connection cache, buffers."
   ;; Cancel timers.
   (cancel-function-timers 'tramp-timeout-session)
 
-  ;; Remove buffers.
+  ;; Remove processes and buffers.
   (dolist (name (tramp-list-tramp-buffers))
+    (when (processp (get-buffer-process name)) (delete-process name))
     (when (bufferp (get-buffer name)) (kill-buffer name)))
 
   ;; The end.

lisp/net/tramp-sh.el

@@ -4049,10 +4049,9 @@ variable PATH."
 	 (format
 	  "PATH=%s; export PATH" (string-join (tramp-get-remote-path vec) ":")))
 	(pipe-buf
-	 (or (with-tramp-connection-property vec "pipe-buf"
-	       (tramp-send-command-and-read
-		vec "getconf PIPE_BUF / 2>/dev/null || echo nil" 'noerror))
-	     4096))
+	 (with-tramp-connection-property vec "pipe-buf"
+	   (tramp-send-command-and-read
+	    vec "getconf PIPE_BUF / 2>/dev/null || echo 4096" 'noerror)))
 	tmpfile)
     (tramp-message vec 5 "Setting $PATH environment variable")
     (if (< (length command) pipe-buf)