Fixed zip file name for 1.4 flame

This fixes that flashing a flame with 1.4 fails

```
Download file: https://pvtbuilds.mozilla.org/pvt/mozilla.org/b2gotoro/nightly/mozilla-b2g30_v1_4-flame/latest/unagi.zip
./auto_flash_from_pvt.sh: line 287: .ldap: No such file or directory
WGET:  -P pvt/flame/v140/USR/latest https://pvtbuilds.mozilla.org/pvt/mozilla.org/b2gotoro/nightly/mozilla-b2g30_v1_4-flame/latest/unagi.zip
--2014-05-07 10:11:22--  https://pvtbuilds.mozilla.org/pvt/mozilla.org/b2gotoro/nightly/mozilla-b2g30_v1_4-flame/latest/unagi.zip
Resolving pvtbuilds.mozilla.org... 63.245.215.32
Connecting to pvtbuilds.mozilla.org|63.245.215.32|:443... connected.
HTTP request sent, awaiting response... 401 Authorization Required
Reusing existing connection to pvtbuilds.mozilla.org:443.
HTTP request sent, awaiting response... 404 Not Found
2014-05-07 10:11:25 ERROR 404: Not Found.
```