use-of-uninitialized-value in ofpbuf prealloc tailroom

use-of-uninitialized-value in ofpbuf prealloc tailroom: a task in MiMo-V2.6-RL-harbor-cyber: MiMo-V2.6-RL Cyber (Harbor) (Harbor dataset). MemorySanitizer: use-of-uninitialized-value in function ofpbuf prealloc tailroom in file openvswitch/lib/ofpbuf.c