CI: add stubs for libcalamares bits, to help pylint

ci/libcalamares/__init__.py

@@ -0,0 +1,9 @@
+#   SPDX-FileCopyrightText: no
+#   SPDX-License-Identifier: CC0-1.0
+#
+# Stubs for part of the Python API from libcalamares
+# (although the **actual** API is presented through
+# Boost::Python, not as a bare C-extension) so that
+# pylint doesn't complain about libcalamares internals.
+
+pass

ci/libcalamares/globalstorage.py

@@ -0,0 +1,9 @@
+#   SPDX-FileCopyrightText: no
+#   SPDX-License-Identifier: CC0-1.0
+#
+# Stubs for part of the Python API from libcalamares
+# (although the **actual** API is presented through
+# Boost::Python, not as a bare C-extension) so that
+# pylint doesn't complain about libcalamares internals.
+
+def value(_): return 1

ci/libcalamares/utils.py

@@ -0,0 +1,15 @@
+#   SPDX-FileCopyrightText: no
+#   SPDX-License-Identifier: CC0-1.0
+#
+# Stubs for part of the Python API from libcalamares
+# (although the **actual** API is presented through
+# Boost::Python, not as a bare C-extension) so that
+# pylint doesn't complain about libcalamares internals.
+
+def debug(_): pass
+
+def warning(_): pass
+
+def gettext_path(): pass
+
+def gettext_languages(): pass