Fix apm_analyzed_spans config directive. (#496)

* Fix apm_analyzed_spans config directive.

In the current configuration, when this puppet module applies `apm_analyzed_spans', the resultant `datadog.yaml` file ignores the configured spans.  The documentation for the agent specifies that the directive should be `analyzed_spans` instead.

More information here:
https://docs.datadoghq.com/agent/apm/?tab=agent630#trace-search

* [apm][spec] fixing analyzed_spans A6 spec tests

Author: dorg-kanderson

manifests/init.pp

@@ -621,7 +621,7 @@
     if $apm_analyzed_spans {
         $apm_analyzed_span_config = {
             'apm_config' => {
-                'apm_analyzed_spans' => $apm_analyzed_spans
+                'analyzed_spans' => $apm_analyzed_spans
             }
         }
     } else {

spec/classes/datadog_agent_spec.rb

@@ -1104,7 +1104,7 @@
               'content' => /^apm_config:\n\ \ enabled: true\n/,
               )}
               it { should contain_file('/etc/datadog-agent/datadog.yaml').with(
-              'content' => /^\ \ apm_analyzed_spans:\n\ \ \ \ foo|bar: 0.5\n\ \ \ \ haz|qux: 0.1\n/,
+              'content' => /^\ \ analyzed_spans:\n\ \ \ \ foo|bar: 0.5\n\ \ \ \ haz|qux: 0.1\n/,
               )}
             end
             context 'with extra_options and Process enabled' do