fix the released token value

[kirk91]

The released token value is always 0 currently, here is the cmd of redis:

1585289102.673865 [0 :37759] "hdel" "semaphore:rmt:host:10.103.113.83:locked" "e9e8feb2-1dee-48a6-889c-3a6fa328fc33:1585289102607926063"
1585289102.673882 [0 :37759] "rpush" "semaphore:rmt:host:10.103.113.83:available" "0"
1585289102.673910 [0 :37759] "pexpire" "semaphore:rmt:host:10.103.113.83" "7200000"

...

1585289103.712386 [0 :37767] "hdel" "semaphore:rmt:host:10.103.112.41:locked" "6b04bd69-641a-453e-b362-1cee2093cbe3:1585289103610856635"
1585289103.712402 [0 :37767] "rpush" "semaphore:rmt:host:10.103.112.41:available" "0"
1585289103.712413 [0 :37767] "pexpire" "semaphore:rmt:host:10.103.112.41" "7200000"