Merge pull request #2623 from suzukaze/fix-indent

Fix indent

src/pool.c

@@ -167,7 +167,7 @@ mrb_pool_realloc(mrb_pool *pool, void *p, size_t oldlen, size_t newlen)
   }
   np = mrb_pool_alloc(pool, newlen);
   if (np == NULL) {
-      return NULL;
+    return NULL;
   }
   memcpy(np, p, oldlen);
   return np;