[FIX] base: avoid duplicated translation entries

For records having multiple translated terms per field (like html fields),
it was possible to have duplicated entries when synchronizing existing
entries with new ones.

openerp/addons/base/ir/ir_translation.py

@@ -491,6 +491,7 @@ class ir_translation(osv.osv):
                             discarded += trans
                         else:
                             trans.write({'src': matches[0], 'state': trans.state})
+                            trans_src.append(matches[0])  # avoid reuse of term
                     else:
                         outdated += trans