Publish test_reports dir

It's a good idea to publish test_reports dir with tree structure.
It will help us to make very flexible test reports without changing
job configuration.
For ex. right now I implemented a patch https://review.openstack.org/#/c/307880/,
that creates separated logs for each fallen test as test folder with browser log,
test log, browser screenshot, and page source. But due to current restrictions
itn's possible to map my reports to jenkins report.
That's why we need this patch.

Change-Id: I124973d9adbaaacf5d3429e6f6684f15de27dc7f
Needed-By: Ie5d972d2a560d4f59666c49dc3bf22fdb48071e8

jenkins/jobs/horizon.yaml

@@ -56,6 +56,7 @@
       - devstack-logs
       - console-log
       - publish-screenshots
+      - publish-test-reports
 
 - publisher:
     name: publish-screenshots
@@ -67,6 +68,17 @@
               source: 'integration_tests_screenshots/**'
               copy-after-failure: true
 
+- publisher:
+    name: publish-test-reports
+    publishers:
+      - scp:
+          site: 'static.openstack.org'
+          files:
+            - target: 'logs/$LOG_PATH/test_reports'
+              source: 'test_reports/**'
+              keep-hierarchy: true
+              copy-after-failure: true
+
 - job:
     name: gate-horizon-selenium-headless
     node: ubuntu-trusty