Add missing critnib initialization

Critnib code assumed that all members are zeroed
in critnib_new. This was not the case since we switched
to using global base alloc.

Author: igchor

src/critnib/critnib.c

@@ -56,6 +56,7 @@
 #include <errno.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <string.h>
 
 #include "base_alloc.h"
 #include "base_alloc_global.h"
@@ -186,6 +187,8 @@ struct critnib *critnib_new(void) {
         return NULL;
     }
 
+    memset(c, 0, sizeof(struct critnib));
+
     void *mutex_ptr = util_mutex_init(&c->mutex);
     if (!mutex_ptr) {
         goto err_free_critnib;