[TEST] Increase base job bucket_span to 1h

The DatafeedJobsIT.testRealtime test fails from time to time.
The test seems to take a long time to execute the flush action
after the lookback. This could make sense as the test produces
a few records over the span of a week with 5 minutes bucket_span.
Thus, flush will end up doing a lot of word to create results
for so many buckets.

This change increases the bucket_span to 1 hour. Hopefully, this
will stop the failures.

Relates elastic/x-pack-elasticsearch#1162

Original commit: elastic/x-pack-elasticsearch@4366907371

plugin/src/test/java/org/elasticsearch/xpack/ml/support/BaseMlIntegTestCase.java

@@ -154,6 +154,7 @@ public abstract class BaseMlIntegTestCase extends ESIntegTestCase {
 
         Detector.Builder d = new Detector.Builder("count", null);
         AnalysisConfig.Builder analysisConfig = new AnalysisConfig.Builder(Collections.singletonList(d.build()));
+        analysisConfig.setBucketSpan(TimeValue.timeValueHours(1));
 
         Job.Builder builder = new Job.Builder();
         builder.setId(jobId);