tempest plugin: save package in temporary dir

This allows tempest tests to run in parallel. The tempest concurrency by
default is set to 3 as the default number of replicas in a deployment to
avoid more than 'replica' number of tests running at the same time that
some of them may fail because of no available pods.

Change-Id: I6e2731ca36376d28573138d4d404c3918801142c

.zuul.yaml

@@ -52,7 +52,9 @@
         TEMPEST_PLUGINS: '/opt/stack/qinling'
       tox_envlist: all-plugin
       tempest_test_regex:  '^(qinling_tempest_plugin.)'
-      tempest_concurrency: 1
+      # Set tempest concurrency to qinling's default number of replicas in a
+      # deployment to avoid tests failing of no avaliable pod.
+      tempest_concurrency: 3
 
 - project:
     check:

qinling_tempest_plugin/tests/base.py

@@ -102,7 +102,8 @@ class BaseQinlingTest(test.BaseTestCase):
         )
         base_name, extention = os.path.splitext(file_path)
         module_name = os.path.basename(base_name)
-        zip_file = os.path.join(tempfile.gettempdir(), '%s.zip' % module_name)
+        temp_dir = tempfile.mkdtemp()
+        zip_file = os.path.join(temp_dir, '%s.zip' % module_name)
 
         if not os.path.isfile(zip_file):
             zf = zipfile.ZipFile(zip_file, mode='w')
@@ -111,6 +112,7 @@ class BaseQinlingTest(test.BaseTestCase):
             finally:
                 zf.close()
 
+        self.addCleanup(os.rmdir, temp_dir)
         self.addCleanup(os.remove, zip_file)
         return zip_file