lib: Make iscsi_realloc() update the freed pointer list

This patch improves the stability of libiscsi by avoiding that
stale pointers are passed to free().

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>

lib/init.c

@@ -49,10 +49,19 @@ void* iscsi_zmalloc(struct iscsi_context *iscsi, size_t size) {
 }
 
 void* iscsi_realloc(struct iscsi_context *iscsi, void* ptr, size_t size) {
+	int i;
 	void * _ptr = realloc(ptr, size);
 	if (_ptr != NULL) {
 		iscsi->reallocs++;
 	}
+	if (ptr != NULL) {
+		for (i = 0; i < iscsi->smalloc_free; i++) {
+			if (iscsi->smalloc_ptrs[i] == ptr) {
+				iscsi->smalloc_ptrs[i] = _ptr;
+				break;
+			}
+		}
+	}
 	return _ptr;
 }