plugin pubsub cache: resync in `synchronise` when node's `sync_state` is not set: synchronisation used to be skipped when the node was existing and `resync` was not set, however the case happens when a node is subscribed but not synchronised, thus this patch update the behaviour to be sure to have the node synchronised. rel 369

syntax: glob
*.pyc
*.pyv
*.swp
*.swo
tags
twistd.log
twistd.pid
bridge_constructor/generated
tests/e2e/report*
_trial_temp/
sat.egg-info
*.un~
dist
MANIFEST
build
ctags_links/
Session.vim
.build
.pytest_cache