Remove event2/event.h include from compat_libevent.h

Only one module was depending on this include (test_helpers.c), and
it was doing so incorrectly.

src/common/compat_libevent.h

@@ -7,8 +7,6 @@
 #include "orconfig.h"
 #include "testsupport.h"
 
-#include <event2/event.h>
-
 void configure_libevent_logging(void);
 void suppress_libevent_log_msg(const char *msg);
 
@@ -19,6 +17,9 @@ void suppress_libevent_log_msg(const char *msg);
   evdns_add_server_port_with_base(tor_libevent_get_base(), \
   (sock),(tcp),(cb),(data));
 
+struct event;
+struct event_base;
+
 void tor_event_free_(struct event *ev);
 #define tor_event_free(ev) \
   FREE_AND_NULL(struct event, tor_event_free_, (ev))

src/test/test_helpers.c

@@ -155,7 +155,7 @@ mock_tor_addr_lookup__fail_on_bad_addrs(const char *name,
 
 /* Helper for test_conn_get_connection() */
 static int
-fake_close_socket(evutil_socket_t sock)
+fake_close_socket(tor_socket_t sock)
 {
   (void)sock;
   return 0;