lxd/main/init/interactive: Clear config.Cluster.ClusterPassword after setting up trust
lxd/main/init/interactive: Clear config.Cluster.ClusterPassword after setting up trust

This avoids triggering a 2nd attempt at setting up trust in clusterPutJoin which would fail when using a single-use join token as a password.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

stgraber/lxd,stgraber/lxd,atxwebs/lxd,hallyn/lxd,stgraber/lxd,atxwebs/lxd,atxwebs/lxd,stgraber/lxd,hallyn/lxd,lxc/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,lxc/lxd,lxc/lxd,atxwebs/lxd,hallyn/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd