Removing unnecessary setup of test database

We are already using pg arrays so the unpickle function in sql/tags.sql
is not needed, at least by the moment. I'm removing it because it was
entering in an infinite loop when creating the test database.

tests/conftest.py

@@ -16,10 +16,6 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import pytest
-import os.path
-from functools import lru_cache
-
-from django.conf import settings
 
 from .fixtures import *
 
@@ -31,18 +27,3 @@ def pytest_addoption(parser):
 def pytest_runtest_setup(item):
     if "slow" in item.keywords and not item.config.getoption("--runslow"):
         pytest.skip("need --runslow option to run")
-
-@lru_cache(maxsize=4)
-def _get_sql():
-    path = os.path.join(settings.BASE_DIR, "sql", "tags.sql")
-    with open(path, "r") as f:
-        return f.read()
-
-
-def on_db_connect(sender, connection, **kwargs):
-    cursor = connection.cursor()
-    cursor.execute(_get_sql())
-
-
-from django.db.backends import signals
-signals.connection_created.connect(on_db_connect)