ansible/ansible — pull request #8591 by tokennyw (2014-08-13 06:15:50+00:00)
Title: Wrap hosts in brackets for synchronize.

In case the host is an IPv6 address, rsync needs brackets to
correctly interpret the colon characters. Wrap the hosts in
so that IPv6 addresses can be used with synchronize. This appears
to be harmless for IPv4 addresses.

I've tested this on my own IPv4 and IPv6 hosts. This should fix issue 8211.