vtysh: fix function prototypes

This makes a whole bunch of vtysh functions static, fixes prototypes for
a few more, and masks user_free() and user_write_config() (both unused.)

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/vtysh/vtysh_config.c b/vtysh/vtysh_config.c
index f9cb6a7..1ddaac0 100644
--- a/vtysh/vtysh_config.c
+++ b/vtysh/vtysh_config.c
@@ -47,19 +47,19 @@
 
 struct list *config_top;
 
-int
+static int
 line_cmp (char *c1, char *c2)
 {
   return strcmp (c1, c2);
 }
 
-void
+static void
 line_del (char *line)
 {
   XFREE (MTYPE_VTYSH_CONFIG_LINE, line);
 }
 
-struct config *
+static struct config *
 config_new ()
 {
   struct config *config;
@@ -67,13 +67,13 @@
   return config;
 }
 
-int
+static int
 config_cmp (struct config *c1, struct config *c2)
 {
   return strcmp (c1->name, c2->name);
 }
 
-void
+static void
 config_del (struct config* config)
 {
   list_delete (config->line);
@@ -82,7 +82,7 @@
   XFREE (MTYPE_VTYSH_CONFIG, config);
 }
 
-struct config *
+static struct config *
 config_get (int index, const char *line)
 {
   struct config *config;
@@ -121,13 +121,13 @@
   return config;
 }
 
-void
+static void
 config_add_line (struct list *config, const char *line)
 {
   listnode_add (config, XSTRDUP (MTYPE_VTYSH_CONFIG_LINE, line));
 }
 
-void
+static void
 config_add_line_uniq (struct list *config, const char *line)
 {
   struct listnode *node, *nnode;
@@ -141,7 +141,7 @@
   listnode_add_sort (config, XSTRDUP (MTYPE_VTYSH_CONFIG_LINE, line));
 }
 
-void
+static void
 vtysh_config_parse_line (const char *line)
 {
   char c;