[FIX] tools: extract terms in correct folder

If two addons path have a common part in the folder name (e.g. `/home/alice/dev`
and `/home/alice/devodoo`), the `get_module_from_path` method may match the
wrong folder.
A file `/home/alice/devodoo/bob/models.py` would wrongly match `/home/alice/dev`
path (due to the lack of separator) and the returned module would be `odoo`
(`"odoo/bob/models.py".split('/')[0]`).

In such scenario, the translations of files (code, static folder, report) would
not be included in the exported translation file.

Force the module path to ends with a folder separator to avoid wrong matching.

Closes #12757

openerp/tools/translate.py

@@ -953,8 +953,9 @@ def trans_generate(lang, modules, cr):
 
     def get_module_from_path(path):
         for (mp, rec) in path_list:
+            mp = os.path.join(mp, '')
             if rec and path.startswith(mp) and os.path.dirname(path) != mp:
-                path = path[len(mp)+1:]
+                path = path[len(mp):]
                 return path.split(os.path.sep)[0]
         return 'base' # files that are not in a module are considered as being in 'base' module