[Libreoffice] Remove "using namespace ::rtl"

[Pierre-André Jacquod]

Hello,

> Even if binfilters is going to be "extracted" from LO, doesn't it worth
I am doing, this, leting it be only an "import" filter.

> to purge "using namespace ::rtl" from it (I think about the people
I think that when "cross-module" cleaning is done, this is worth to do
it also within binfilter: to get ride of old style, to be consistent
with the rest. But should not be top 1 priority :- )

regards
Pierre-André