Fix double close in GetTreeBytes.

calculate_dir_size closes the fd that it receives.

Bug: http://b/80446935
Test: treehugger
Change-Id: I56a428cd7eb78e56c55434628c1c7b2b87637c81

Utils.cpp

@@ -523,9 +523,7 @@ uint64_t GetTreeBytes(const std::string& path) {
         PLOG(WARNING) << "Failed to open " << path;
         return -1;
     } else {
-        uint64_t res = calculate_dir_size(dirfd);
-        close(dirfd);
-        return res;
+        return calculate_dir_size(dirfd);
     }
 }