Drop import fallback for Python 2

cPickle no longer exists in Python 3 and pickle should be used always.

Change-Id: I5ddedb3e996d9a0679bab38ea94263886274ece4

watcher/db/sqlalchemy/job_store.py

@@ -16,23 +16,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from oslo_serialization import jsonutils
+import pickle
 
 from apscheduler.jobstores.base import ConflictingIdError
 from apscheduler.jobstores import sqlalchemy
 from apscheduler.util import datetime_to_utc_timestamp
 from apscheduler.util import maybe_ref
 from apscheduler.util import utc_timestamp_to_datetime
+from oslo_serialization import jsonutils
 
 from watcher.common import context
 from watcher.common import service
 from watcher import objects
 
-try:
-    import cPickle as pickle
-except ImportError:  # pragma: nocover
-    import pickle
-
 from sqlalchemy import Table, MetaData, select, and_, null
 from sqlalchemy.exc import IntegrityError