Make sure the right caldav version is installed.

modoboa_installer/scripts/modoboa.py

@@ -91,6 +91,10 @@ class Modoboa(base.Installer):
         if sys.version_info.major == 2 and sys.version_info.micro < 9:
             # Add extra packages to fix the SNI issue
             packages += ["pyOpenSSL"]
+        if "modoboa-radicale" in self.extensions:
+            # Temp. fix
+            packages += [
+                "https://github.com/modoboa/caldav/tarball/master#egg=caldav"]
         python.install_packages(packages, self.venv_path, sudo_user=self.user)
         if self.devmode:
             # FIXME: use dev-requirements instead