Remove a few unnecessary #includes.

Some spotted by Michael Tokarev.

src/conf.c

@@ -26,6 +26,7 @@
 #include "avl_tree.h"
 #include "connection.h"
 #include "conf.h"
+#include "list.h"
 #include "logger.h"
 #include "netutl.h"				/* for str2address */
 #include "protocol.h"

src/connection.c

@@ -23,10 +23,7 @@
 
 #include "avl_tree.h"
 #include "conf.h"
-#include "list.h"
 #include "logger.h"
-#include "net.h"				/* Don't ask. */
-#include "netutl.h"
 #include "subnet.h"
 #include "utils.h"
 #include "xalloc.h"

src/connection.h

@@ -45,7 +45,6 @@ typedef struct connection_status_t {
 } connection_status_t;
 
 #include "edge.h"
-#include "list.h"
 #include "net.h"
 #include "node.h"
 

src/net_packet.c

@@ -43,7 +43,6 @@
 #include "ethernet.h"
 #include "event.h"
 #include "graph.h"
-#include "list.h"
 #include "logger.h"
 #include "net.h"
 #include "netutl.h"

src/node.h

@@ -24,7 +24,6 @@
 #include "avl_tree.h"
 #include "connection.h"
 #include "event.h"
-#include "list.h"
 #include "subnet.h"
 
 typedef struct node_status_t {