Fix LOG_PATH to use 7char uuid

The zuul variable, LOG_PATH, is meant to be in the format of how
openstack stores its logs. OpenStack actually only uses the first 7
characters of the uuid in the path so we need to limit what we send
via the gearman variables here too

Change-Id: I2a3260c242e1fe895c650df276951ef23d7dc7c9
diff --git a/tests/test_scheduler.py b/tests/test_scheduler.py
index ceb1588..dbcfd1b 100755
--- a/tests/test_scheduler.py
+++ b/tests/test_scheduler.py
@@ -2700,7 +2700,7 @@
         self.assertEqual(
             "https://storage.example.org/V1/AUTH_account/merge_logs/1/1/1/"
             "gate/test-merge/",
-            self.builds[0].parameters['SWIFT_logs_URL'][:-32])
+            self.builds[0].parameters['SWIFT_logs_URL'][:-7])
         self.assertEqual(5,
                          len(self.builds[0].parameters['SWIFT_logs_HMAC_BODY'].
                              split('\n')))
@@ -2709,7 +2709,7 @@
         self.assertEqual(
             "https://storage.example.org/V1/AUTH_account/logs/1/1/1/"
             "gate/test-test/",
-            self.builds[1].parameters['SWIFT_logs_URL'][:-32])
+            self.builds[1].parameters['SWIFT_logs_URL'][:-7])
         self.assertEqual(5,
                          len(self.builds[1].parameters['SWIFT_logs_HMAC_BODY'].
                              split('\n')))
@@ -2718,7 +2718,7 @@
         self.assertEqual(
             "https://storage.example.org/V1/AUTH_account/stash/1/1/1/"
             "gate/test-test/",
-            self.builds[1].parameters['SWIFT_MOSTLY_URL'][:-32])
+            self.builds[1].parameters['SWIFT_MOSTLY_URL'][:-7])
         self.assertEqual(5,
                          len(self.builds[1].
                              parameters['SWIFT_MOSTLY_HMAC_BODY'].split('\n')))
diff --git a/zuul/launcher/gearman.py b/zuul/launcher/gearman.py
index ec60f9e..57db7dc 100644
--- a/zuul/launcher/gearman.py
+++ b/zuul/launcher/gearman.py
@@ -302,7 +302,7 @@
         # The destination_path is a unqiue path for this build request
         # and generally where the logs are expected to be placed
         destination_path = os.path.join(item.change.getBasePath(),
-                                        pipeline.name, job.name, uuid)
+                                        pipeline.name, job.name, uuid[:7])
         params['BASE_LOG_PATH'] = item.change.getBasePath()
         params['LOG_PATH'] = destination_path