http: Add some logging to try to diagnose an intermittent shutdown issue.

src/ssb.c

@@ -1,5 +1,6 @@
 #include "ssb.h"
 
+#include "http.h"
 #include "log.h"
 #include "mem.h"
 #include "ssb.connections.h"
@@ -2711,6 +2712,7 @@ void tf_ssb_destroy(tf_ssb_t* ssb)
 			tf_printf("--\n");
 			uv_print_all_handles(ssb->loop, stdout);
 		}
+		tf_http_debug_destroy();
 		uv_run(ssb->loop, UV_RUN_ONCE);
 	}