fix for: https://github.com/saltstack/salt/issues/27373
fix for: https://github.com/saltstack/salt/issues/27373

Setup::DownloadWindowsDlls is downloading and writing the file as
a text not a binary file.

When creating the file handle to write the binary after being download from salt's
dependency repo, the file handle was being created with just the 'write' attribute,
however it also needs the 'binary' attribute.

Change-Id: I2f67d27ee847cd7808a78cd5ec0b2151d6a0c0e7

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt