net: add missing include file

To fix building error:

CC net/vde.o
net/vde.c: In function ‘vde_cleanup’:
net/vde.c:65:5: error: implicit declaration of function ‘qemu_set_fd_handler’ [-Werror=implicit-function-declaration] net/vde.c:65:5: error: nested extern declaration of ‘qemu_set_fd_handler’ [-Werror=nested-externs]
cc1: all warnings being treated as errors

Signed-off-by Liming Wang <[email protected]>

---
 net/vde.c |    1 +
 1 file changed, 1 insertion(+)

net/vde.c +1 -1

index 754a141..4dea32d 100644
@@ -29,6 +29,7 @@
 #include "clients.h"
 #include "qemu-common.h"
 #include "qemu/option.h"
+#include "qemu/main-loop.h"
 
 typedef struct VDEState {
     NetClientState nc;
--

1.7.9.5