When running bootstrap-aio.sh twice with latest ansible runs OR when
providing your own resolvers from inside a unicode file, the
lxc_cache_resolvers will be generated as this:
lxc_cache_resolvers: [u'nameserver1',u'nameserver2']
This commit fixes this behaviour, and allow provided lxc_cache_resolvers
into CLI, from a file, or generated from hosts (when not set).
Change-Id: I6cb34e1a922d374ddccc37fd7bf0fd5ff9e14b88
Signed-off-by: Jean-Philippe Evrard <jean-philippe@evrard.me>