Make sure deployer doesn't timeout before amulet

Pass through a slightly longer timeout value to deployer so that
we can handle the timeout in amulet.
Make JujuVersion handle missing patch versions

Makes str(JujuVersion()) == '1.2' instead of '1.2.0' when 'juju version' == 1.2

This was necessary as a test failure was exposed with the current version of juju,
which doesn't have a patch version.