Remove duplicated field "revision" from ecs_task because it's already…

… defined as a tag there (influxdata#8574)

plugins/inputs/ecs/README.md

@@ -87,7 +87,6 @@ present in the metadata/stats endpoints.
     - id
     - name
   - fields:
-    - revision (string)
     - desired_status (string)
     - known_status (string)
     - limit_cpu (float)
@@ -226,7 +225,7 @@ present in the metadata/stats endpoints.
 ### Example Output
 
 ```
-ecs_task,cluster=test,family=nginx,host=c4b301d4a123,revision=2,task_arn=arn:aws:ecs:aws-region-1:012345678901:task/a1234abc-a0a0-0a01-ab01-0abc012a0a0a revision="2",desired_status="RUNNING",known_status="RUNNING",limit_cpu=0.5,limit_mem=512 1542641488000000000
+ecs_task,cluster=test,family=nginx,host=c4b301d4a123,revision=2,task_arn=arn:aws:ecs:aws-region-1:012345678901:task/a1234abc-a0a0-0a01-ab01-0abc012a0a0a desired_status="RUNNING",known_status="RUNNING",limit_cpu=0.5,limit_mem=512 1542641488000000000
 ecs_container_mem,cluster=test,com.amazonaws.ecs.cluster=test,com.amazonaws.ecs.container-name=~internal~ecs~pause,com.amazonaws.ecs.task-arn=arn:aws:ecs:aws-region-1:012345678901:task/a1234abc-a0a0-0a01-ab01-0abc012a0a0a,com.amazonaws.ecs.task-definition-family=nginx,com.amazonaws.ecs.task-definition-version=2,family=nginx,host=c4b301d4a123,id=e6af031b91deb3136a2b7c42f262ed2ab554e2fe2736998c7d8edf4afe708dba,name=~internal~ecs~pause,revision=2,task_arn=arn:aws:ecs:aws-region-1:012345678901:task/a1234abc-a0a0-0a01-ab01-0abc012a0a0a active_anon=40960i,active_file=8192i,cache=790528i,pgpgin=1243i,total_pgfault=1298i,total_rss=40960i,limit=1033658368i,max_usage=4825088i,hierarchical_memory_limit=536870912i,rss=40960i,total_active_file=8192i,total_mapped_file=618496i,usage_percent=0.05349543109392212,container_id="e6af031b91deb3136a2b7c42f262ed2ab554e2fe2736998c7d8edf4afe708dba",pgfault=1298i,pgmajfault=6i,pgpgout=1040i,total_active_anon=40960i,total_inactive_file=782336i,total_pgpgin=1243i,usage=552960i,inactive_file=782336i,mapped_file=618496i,total_cache=790528i,total_pgpgout=1040i 1542642001000000000
 ecs_container_cpu,cluster=test,com.amazonaws.ecs.cluster=test,com.amazonaws.ecs.container-name=~internal~ecs~pause,com.amazonaws.ecs.task-arn=arn:aws:ecs:aws-region-1:012345678901:task/a1234abc-a0a0-0a01-ab01-0abc012a0a0a,com.amazonaws.ecs.task-definition-family=nginx,com.amazonaws.ecs.task-definition-version=2,cpu=cpu-total,family=nginx,host=c4b301d4a123,id=e6af031b91deb3136a2b7c42f262ed2ab554e2fe2736998c7d8edf4afe708dba,name=~internal~ecs~pause,revision=2,task_arn=arn:aws:ecs:aws-region-1:012345678901:task/a1234abc-a0a0-0a01-ab01-0abc012a0a0a usage_in_kernelmode=0i,throttling_throttled_periods=0i,throttling_periods=0i,throttling_throttled_time=0i,container_id="e6af031b91deb3136a2b7c42f262ed2ab554e2fe2736998c7d8edf4afe708dba",usage_percent=0,usage_total=26426156i,usage_in_usermode=20000000i,usage_system=2336100000000i 1542642001000000000
 ecs_container_cpu,cluster=test,com.amazonaws.ecs.cluster=test,com.amazonaws.ecs.container-name=~internal~ecs~pause,com.amazonaws.ecs.task-arn=arn:aws:ecs:aws-region-1:012345678901:task/a1234abc-a0a0-0a01-ab01-0abc012a0a0a,com.amazonaws.ecs.task-definition-family=nginx,com.amazonaws.ecs.task-definition-version=2,cpu=cpu0,family=nginx,host=c4b301d4a123,id=e6af031b91deb3136a2b7c42f262ed2ab554e2fe2736998c7d8edf4afe708dba,name=~internal~ecs~pause,revision=2,task_arn=arn:aws:ecs:aws-region-1:012345678901:task/a1234abc-a0a0-0a01-ab01-0abc012a0a0a container_id="e6af031b91deb3136a2b7c42f262ed2ab554e2fe2736998c7d8edf4afe708dba",usage_total=26426156i 1542642001000000000

plugins/inputs/ecs/ecs.go

@@ -166,7 +166,6 @@ func resolveEndpoint(ecs *Ecs) {
 
 func (ecs *Ecs) accTask(task *Task, tags map[string]string, acc telegraf.Accumulator) {
 	taskFields := map[string]interface{}{
-		"revision":       task.Revision,
 		"desired_status": task.DesiredStatus,
 		"known_status":   task.KnownStatus,
 		"limit_cpu":      task.Limits["CPU"],