[Translators] some typos in source

[Thomas Bellmann]

In
#: src/plugins/tnef_parse/tnef_parse.c:116
msgid "Failed to write the part data."
msgstr ""

shouldn't this be:
msgid "Failed to write the data part." ?

I think I wont be able to get some tnef (whatever this is :) ) data and
then trigger this error message somehow so I ask.