Strip out commented-out translations after update

This is necessary because:
- Transifex runs 'msgfmt -c' on any uploaded .po file
- pybabel adds a spurious '#~ msgid ""' to the end of some files
- 'msgfmt -c' ignores that this is commented out, and treats it
  as a syntax error (clashing with the top file definition)

i2p2www/translations/he/LC_MESSAGES/get-involved.po

@@ -4088,6 +4088,3 @@ msgid ""
 "href=\"http://%(zzz)s/forums/14\">translation forum on %(zzz)s</a>."
 msgstr ""
 
-#~ msgid ""
-#~ msgstr ""
-