global: remove unnecessary includes from headers.

Each header should only include the other headers it needs to compile;
`devtools/reduce-includes.sh */*.h` does this.  The C files then need
additional includes if they don't compile.

And remove the entirely useless wire/onion_wire.h, which only serves to include wire/onion_wiregen.h.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

db/common.h

@@ -2,11 +2,8 @@
 #define LIGHTNING_DB_COMMON_H
 #include "config.h"
 #include <ccan/list/list.h>
-#include <ccan/short_types/short_types.h>
-#include <ccan/strset/strset.h>
 #include <common/autodata.h>
 #include <common/utils.h>
-#include <stdarg.h>
 
 /**
  * Macro to annotate a named SQL query.

db/utils.c

@@ -1,4 +1,5 @@
 #include "config.h"
+#include <ccan/strset/strset.h>
 #include <ccan/tal/str/str.h>
 #include <common/trace.h>
 #include <common/utils.h>