tests: Use mock from unittest

Dockerfile.test

@@ -13,7 +13,6 @@ RUN  dnf -y install \
   python3-gevent \
   python3-magic \
   python3-mako \
-  python3-mock \
   python3-pocketlint \
   python3-pycdlib \
   python3-pylint \

tests/pylorax/test_recipes.py

@@ -15,10 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 import os
-import mock
 import shutil
 import tempfile
 import unittest
+from unittest import mock
 
 import pylorax.api.recipes as recipes
 from pylorax.api.compose import add_customizations, customize_ks_template

tests/pylorax/test_workspace.py

@@ -15,10 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 import os
-import mock
 import shutil
 import tempfile
 import unittest
+from unittest import mock
 
 import pylorax.api.recipes as recipes
 from pylorax.api.workspace import workspace_dir, workspace_read, workspace_write, workspace_delete