REORG: include: move signal.h to haproxy/signal{,-t}.h

No change was necessary. Include from wdt.c was dropped since unneeded.
diff --git a/src/ev_evports.c b/src/ev_evports.c
index cfd053b..3d60247 100644
--- a/src/ev_evports.c
+++ b/src/ev_evports.c
@@ -19,6 +19,7 @@
 #include <syslog.h>
 
 #include <haproxy/api.h>
+#include <haproxy/signal.h>
 #include <haproxy/thread-t.h>
 #include <haproxy/ticks.h>
 #include <haproxy/time.h>
@@ -28,7 +29,6 @@
 #include <haproxy/activity.h>
 #include <haproxy/fd.h>
 #include <proto/log.h>
-#include <proto/signal.h>
 
 /*
  * Private data: