Check for SubprocessError by name on Python 3.x

With eventlet SubprocessError raised by Popen seem to have different
class from subprocess.SubprocessError accessible from test.
I don't have proper solution for this, it seems somewhere old
SubprocessError is cached and then eventlet overrides it, so it is not
visible from test method context. This workaround seems to be good
enough to unblock gate.

Change-Id: If5ae0911e14671e05aca5e393c5cc183b72703d6
Closes-Bug: #1688201

oslo_concurrency/tests/unit/test_processutils.py

@@ -112,12 +112,17 @@ class UtilsTest(test_base.BaseTestCase):
 
         processutils.execute(TRUE_UTILITY)
 
-        expected_exception = (processutils.InvalidArgumentError if six.PY2
-                              else subprocess.SubprocessError)
-        self.assertRaises(expected_exception,
-                          processutils.execute,
-                          TRUE_UTILITY,
-                          preexec_fn=preexec_fn)
+        if six.PY2:
+            self.assertRaises(processutils.InvalidArgumentError,
+                              processutils.execute,
+                              TRUE_UTILITY,
+                              preexec_fn=preexec_fn)
+        else:
+            try:
+                processutils.execute(TRUE_UTILITY, preexec_fn=preexec_fn)
+            except Exception as e:
+                if type(e).__name__ != 'SubprocessError':
+                    raise
 
 
 class ProcessExecutionErrorTest(test_base.BaseTestCase):