set CORS allow origin * in the right place

[mallochine]

sry about that. I didn't properly test last time. I tested it properly this time.

How to test

1. setup blobber to run on localhost as instructed in README.
2. Run this curl:

  curl -i 'http://localhost:5051/v1/file/upload/4e863327cf888dfd6ae87ebc7dbd6771741a4d7a0288527f213dd9a243dffad4' \
    -X 'OPTIONS' \
    -H 'Accept: */*' \
    -H 'Access-Control-Request-Method: POST' \
    -H 'Access-Control-Request-Headers: x-app-client-id,x-app-client-key' \
    -H 'Origin: http://localhost:82' \
    -H 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36' \
    -H 'Sec-Fetch-Mode: cors' \
    --compressed

Expect this output:

HTTP/1.1 200 OK
Access-Control-Allow-Headers: X-App-Client-Id,X-App-Client-Key
Access-Control-Allow-Origin: *
Date: Sun, 23 May 2021 00:50:00 GMT
Content-Length: 0