hv: Change variable type to bool

The variable execute_shutdown is only assigned the values true and
false. Change its type to bool.

The simplified semantic patch that find this problem is as
follows (http://coccinelle.lip6.fr/):

@exists@
type T;
identifier b;
@@
- T
+ bool
  b = ...;
  ... when any
  b = \(true\|false\)
Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/hv_util.c

@@ -82,7 +82,7 @@ static void shutdown_onchannelcallback(void *context)
 	struct vmbus_channel *channel = context;
 	u32 recvlen;
 	u64 requestid;
-	u8  execute_shutdown = false;
+	bool execute_shutdown = false;
 	u8  *shut_txf_buf = util_shutdown.recv_buffer;
 
 	struct shutdown_msg_data *shutdown_msg;