Add Share Migration tempest functional tests

This patch adds functional tests for Share Migration,
running on generic driver DHSS = true mode.

Implements: blueprint share-migration
Change-Id: I64b0a3ee77b27278cc294f72702408a27888e0e9
diff --git a/manila_tempest_tests/config.py b/manila_tempest_tests/config.py
index ea1f678..caa4589 100644
--- a/manila_tempest_tests/config.py
+++ b/manila_tempest_tests/config.py
@@ -151,4 +151,11 @@
     cfg.StrOpt("client_vm_flavor_ref",
                default="100",
                help="Flavor used for client vm in scenario tests."),
+    cfg.IntOpt("migration_timeout",
+               default=1200,
+               help="Time to wait for share migration before "
+                    "timing out (seconds)."),
+    cfg.BoolOpt("migration_enabled",
+                default=True,
+                help="Enable or disable migration tests."),
 ]