python.d.plugin update (#4936)

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##### Summary
Fix: #4756

`python.d.plugin` updates:
  * remove `retries` option 
  * make `penalty` configurable (enabled by default, max is 10 minutes)

> penalty indicates whether to apply penalty to update_every in case of failures.
> Penalty will increase every 5 failed updates in a row. Maximum penalty is 10 minutes.
> penalty: yes

##### Component Name

`python.d.plugin`

##### Additional Information

collectors/python.d.plugin/postgres/postgres.chart.py

@@ -19,7 +19,6 @@ from bases.FrameworkServices.SimpleService import SimpleService
 # default module values
 update_every = 1
 priority = 60000
-retries = 60
 
 METRICS = {
     'DATABASE': [