If the state variable is krealloced successfully, map->osd_state will be
freed, once following two reallocation failed, and exit the function
without resetting map->osd_state, map->osd_state become a wild pointer.

fix it by resetting them after krealloc successfully.
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>