Refresh pillar only if minion is connected to master
Refresh pillar only if minion is connected to master

Added logic to refresh the pillar only if the minion is connected
to the master in `Minion.pillar_refresh()`. This matches the existing
logic in `Minion._post_master_init()`. This allows `pillar_refresh`
and `grains_refresh` events to be handled without throwing an exception
if the minion is not connected to the master (eg when `master_type` is
`disable`).

Signed-off-by: Sergey Kizunov <dfddabaa9af05982b01940b837a87844148069c9@ni.com>

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt