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

3 files changed, 4 insertions, 9 deletions

diff --git a/collectors/python.d.plugin/go_expvar/README.md b/collectors/python.d.plugin/go_expvar/README.md
index e3356e1f1c..782f08133b 100644
--- a/collectors/python.d.plugin/go_expvar/README.md
+++ b/collectors/python.d.plugin/go_expvar/README.md
@@ -169,7 +169,6 @@ and its base `UrlService` class. These are:
 
     update_every: 1          # the job's data collection frequency
     priority:     60000      # the job's order on the dashboard
-    retries:      60         # the job's number of restoration attempts
     user:         admin      # use when the expvar endpoint is protected by HTTP Basic Auth
     password:     sekret     # use when the expvar endpoint is protected by HTTP Basic Auth
 
diff --git a/collectors/python.d.plugin/go_expvar/go_expvar.chart.py b/collectors/python.d.plugin/go_expvar/go_expvar.chart.py
index 76e8b72ec6..bff5d32e7f 100644
--- a/collectors/python.d.plugin/go_expvar/go_expvar.chart.py
+++ b/collectors/python.d.plugin/go_expvar/go_expvar.chart.py
@@ -11,8 +11,6 @@ from bases.FrameworkServices.UrlService import UrlService
 # default module values (can be overridden per job in `config`)
 # update_every = 2
 priority = 60000
-retries = 60
-
 
 MEMSTATS_CHARTS = {
     'memstats_heap': {
diff --git a/collectors/python.d.plugin/go_expvar/go_expvar.conf b/collectors/python.d.plugin/go_expvar/go_expvar.conf
index af89158aa1..4b821cde96 100644
--- a/collectors/python.d.plugin/go_expvar/go_expvar.conf
+++ b/collectors/python.d.plugin/go_expvar/go_expvar.conf
@@ -27,11 +27,9 @@
 # If unset, the default for python.d.plugin is used.
 # priority: 60000
 
-# retries sets the number of retries to be made in case of failures.
-# If unset, the default for python.d.plugin is used.
-# Attempts to restore the service are made once every update_every
-# and only if the module has collected values in the past.
-# retries: 60
+# 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
 
 # autodetection_retry sets the job re-check interval in seconds.
 # The job is not deleted if check fails.
@@ -53,7 +51,7 @@
 #                             # JOBs sharing a name are mutually exclusive
 #     update_every: 1         # the JOB's data collection frequency
 #     priority: 60000         # the JOB's order on the dashboard
-#     retries: 60             # the JOB's number of restoration attempts
+#     penalty: yes            # the JOB's penalty
 #     autodetection_retry: 0  # the JOB's re-check interval in seconds
 #
 # Additionally to the above, this plugin also supports the following: