Remove hyphen from rand_name calls in volume tests

data_utils.rand_name() appends randam charactors with a hypen like:

 def rand_name(name=''):
     randbits = str(random.randint(1, 0x7fffffff))
     if name:
         return name + '-' + randbits

So it is not necessary to specify a hypen in caller side.
This patch removes a hypen in volume tests.

Change-Id: I1ea38961053cf751b14e261321d6695a8c11dd54
diff --git a/tempest/api/volume/admin/test_snapshots_actions.py b/tempest/api/volume/admin/test_snapshots_actions.py
index cb55869..db026c1 100644
--- a/tempest/api/volume/admin/test_snapshots_actions.py
+++ b/tempest/api/volume/admin/test_snapshots_actions.py
@@ -31,7 +31,7 @@
         super(SnapshotsActionsV2Test, cls).resource_setup()
 
         # Create a test shared volume for tests
-        vol_name = data_utils.rand_name(cls.__name__ + '-Volume-')
+        vol_name = data_utils.rand_name(cls.__name__ + '-Volume')
         cls.name_field = cls.special_fields['name_field']
         params = {cls.name_field: vol_name}
         cls.volume = \
@@ -40,7 +40,7 @@
                                                   'available')
 
         # Create a test shared snapshot for tests
-        snap_name = data_utils.rand_name(cls.__name__ + '-Snapshot-')
+        snap_name = data_utils.rand_name(cls.__name__ + '-Snapshot')
         params = {cls.name_field: snap_name}
         cls.snapshot = \
             cls.client.create_snapshot(cls.volume['id'], **params)