Update CHANGELOG with RP admin page fix
Update CHANGELOG with RP admin page fix

Adds a note about fixing a bug with the admin page where users were
unable to update retention policies.

mark-rushakoff/influxdb,influxdb/influxdb,li-ang/influxdb,influxdb/influxdb,nooproblem/influxdb,influxdb/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,li-ang/influxdb,nooproblem/influxdb,nooproblem/influxdb,influxdata/influxdb,mark-rushakoff/influxdb,nooproblem/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,influxdb/influxdb,influxdata/influxdb,nooproblem/influxdb,mark-rushakoff/influxdb,mark-rushakoff/influxdb