Rsync from Windows host does not work

[mkuzmin]

Here is an issue introduced in #6568.
On Windows host, if an username is more than 8 symbols, than Dir.tmpdir() is resolved to a special path like TEMP=C:\Users\MICHAE~1.KUZ\AppData\Local\Temp.
cygwin_path() cannot convert it correctly, ControlPath is set to incorrect value, and Rsync fails:

==> teamcity: Rsyncing folder: /c/Users/michael.kuzmin/Projects/forks/vagrant/tasks/ => /vagrant
There was an error when attempting to rsync a synced folder.
Please inspect the error message below for more info.

Host path: /c/Users/michael.kuzmin/Projects/forks/vagrant/tasks/
Guest path: /vagrant
Command: rsync --verbose --archive --delete -z --copy-links --chmod=ugo=rwX --no-perms --no-owner --no-group --rsync-path
sudo rsync -e ssh -p 22 -o ControlMaster=auto -o ControlPath=C:/Users/MICHAE~1.KUZ/AppData/Local/Temp/ssh.196 -o ControlPersist=10m -o StrictHostKeyChecking=no -o IdentitiesOnly=true -o UserKnownHostsFile=/dev/null -i 'C:/Users/michael.kuzmin/Projects/forks/vagrant/.vagrant/machines/teamcity/vsphere/private_key' --exclude .vagrant/ /c/Users/michael.kuzmin/Projects/forks/vagrant/tasks/ jetbrains@172.20.160.212:/vagrant
Error: This rsync lacks old-style --compress due to its external zlib.  Try -zz.
Continuing without compression.

Warning: Permanently added '172.20.160.212' (ECDSA) to the list of known hosts.
mm_receive_fd: no message header
process_mux_new_session: failed to receive fd 0 from slave
mux_client_request_session: read from master failed: Connection reset by peer
Failed to connect to new control master
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: error in rsync protocol data stream (code 12) at io.c(226) [sender=3.1.1]

[arthuroy]

See #6702 , the error happens even the usename is less than 8 symbols.

[mkuzmin]

#6702 is more active, so I close this one as a duplicate.