Replace deprecated max_failure_precent sla

The new sla is a failure_rate with min/max sub-keys. Update the
documentation and examples to reflect this.

Change-Id: Id947e4684aa84fe7d6c239a28b92e2a893ddaf66

doc/source/tutorial/step_3_adding_success_criteria_for_benchmarks.rst

@@ -41,7 +41,9 @@ To configure the SLA, add the *"sla"* section to the configuration of the corres
                 },
                 "sla": {
                     "max_seconds_per_iteration": 10,
-                    "max_failure_percent": 25
+                    "failure_rate": {
+                        "max": 25
+                    }
                 }
             }
         ]

rally/cmd/commands/info.py

@@ -162,7 +162,8 @@ class InfoCommands(object):
                 "assosiated value, e.g.:\n\n"
                 "  sla:\n"
                 "    max_seconds_per_iteration: 4\n"
-                "    max_failure_percent: 1"
+                "    failure_rate:\n"
+                "      max: 1"
                 "\n\n" +
                 self._compose_table("List of SLA checks", sla) +
                 "To get information about specific SLA checks, run:\n"

samples/tasks/sla/README.rst

@@ -9,10 +9,10 @@ with contracted values such as maximum error rate or minimum response time.
 Currently supported criteria:
 
 
-max_failure_percent
+failure_rate
 -------------------
 
-Maximum allowed failure rate in percent.
+A maximum and/or a minimum failure rate expressed as max or min sub-keys.
 
 
 max_seconds_per_iteration

samples/tasks/sla/create-and-delete-user.json

@@ -11,7 +11,9 @@
             },
             "sla": {
                 "max_seconds_per_iteration": 4,
-                "max_failure_percent": 1
+                "failure_rate": {
+                    "max": 1
+                }
             }
         }
     ]

samples/tasks/sla/create-and-delete-user.yaml

@@ -9,4 +9,5 @@
         concurrency: 10
       sla:
         max_seconds_per_iteration: 4
-        max_failure_percent: 1
+        failure_rate:
+          max: 1