msg: Fix incorrect queues initializations

From core/include/msg.h:

/**
 * @brief Initialize the current thread's message queue.
 *
 * @param[in] array Pointer to preallocated array of ``msg_t`` structures, must
 *                  not be NULL.
 * @param[in] num   Number of ``msg_t`` structures in array.
 *                  **MUST BE POWER OF TWO!**
 *
 * @return 0, if successful
 * @return -1, on error
 */
int msg_init_queue(msg_t *array, int num);

sizeof(array) does does not compute an array size. Replace calls to sizeof()
with proper values

Closes #3269.

Fix two crashes in the tests and probably more in the network stack.

sys/net/link_layer/ping/ping.c

@@ -140,7 +140,7 @@ static void *l2_pkt_handler(void *unused)
     radio_packet_t *p;
     l2_ping_payload_t *pp;
 
-    msg_init_queue(msg_q, sizeof(msg_q));
+    msg_init_queue(msg_q, RCV_BUFFER_SIZE);
 
     while (1) {
         msg_receive(&m);

sys/net/routing/aodvv2/aodv.c

@@ -242,7 +242,7 @@ static void *_aodv_sender_thread(void *arg)
     (void) arg;
 
     msg_t msgq[RCV_MSG_Q_SIZE];
-    msg_init_queue(msgq, sizeof msgq);
+    msg_init_queue(msgq, RCV_MSG_Q_SIZE);
     AODV_DEBUG("_aodv_sender_thread initialized.\n");
 
     while (true) {

tests/vtimer_msg/main.c

@@ -26,6 +26,8 @@
 #include "thread.h"
 #include "msg.h"
 
+#define MSG_QUEUE_SIZE 1
+
 char timer_stack[THREAD_STACKSIZE_MAIN];
 char timer_stack_local[THREAD_STACKSIZE_MAIN];
 
@@ -49,8 +51,8 @@ void *timer_thread(void *arg)
     /* we need a queue if the second message arrives while the first is still processed */
     /* without a queue, the message would get lost */
     /* because of the way this timer works, there can be max 1 queued message */
-    msg_t msgq[1];
-    msg_init_queue(msgq, sizeof(msgq));
+    msg_t msgq[MSG_QUEUE_SIZE];
+    msg_init_queue(msgq, MSG_QUEUE_SIZE);
 
     while (1) {
         msg_t m;

tests/vtimer_msg_diff/main.c

@@ -31,6 +31,8 @@
 #define MAXCOUNT 100
 #define MAXDIFF 10000
 
+#define MSG_QUEUE_SIZE 16
+
 char timer_stack[THREAD_STACKSIZE_MAIN*4];
 
 struct timer_msg {
@@ -56,8 +58,8 @@ void *timer_thread(void *arg)
     (void) arg;
     printf("This is thread %" PRIkernel_pid "\n", thread_getpid());
 
-    msg_t msgq[16];
-    msg_init_queue(msgq, sizeof(msgq));
+    msg_t msgq[MSG_QUEUE_SIZE];
+    msg_init_queue(msgq, MSG_QUEUE_SIZE);
 
     while (1) {
         msg_t m;