[FIX] tools: correctly export the non-module translations

8ac39287 introdcude a way to export the source terms not located inside an
addons module (e.g. error messages in openerp/service/models.py)

0529a7f9 fixed a bug in the get_module_from_path with addons path with similar
names.

The above commit introduced a regression making files located outside of an
addons path to be wrongly considered as a module
e.g. openerp/service/models.py used not to match any module and was considered
correctly as belonging to base module
After, 0529a7f9, '~/openerp/service' being different than '~/openerp/service/'
the module was considered as 'models.py' (which is incorrect).

Compare correctly both parent path to have a correct match

Fixes # 19907

openerp/tools/translate.py

@@ -958,7 +958,8 @@ 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:
+            dirname = os.path.join(os.path.dirname(path), '')
+            if rec and path.startswith(mp) and dirname != mp:
                 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