datasource: use only underscore in slug (#54979)

tests/admin_pages/test_datasource.py

@@ -567,7 +567,7 @@ def test_data_sources_import(pub):
     assert NamedDataSource.count() == 3
     assert NamedDataSource.get(1).slug == 'baaaz'
     assert NamedDataSource.get(2).slug == 'foobar'
-    assert NamedDataSource.get(3).slug == 'foobar-1'
+    assert NamedDataSource.get(3).slug == 'foobar_1'
 
     # import an invalid file
     resp = app.get('/backoffice/settings/data-sources/')

wcs/data_sources.py

@@ -559,7 +559,7 @@ class NamedDataSource(XmlStorableObject):
             if obj.id == self.id:
                 break
             suffix_no += 1
-            new_slug = '%s-%s' % (base_new_slug, suffix_no)
+            new_slug = '%s_%s' % (base_new_slug, suffix_no)
         return new_slug
 
     def get_admin_url(self):