- remove "using namespace std;"
- &vector[0] to vector.data()
- use nullptr in OPENSSL

Change-Id: Ib4067b0256801f94d448bc8d3faf5a2902d694e5
Reviewed-on: https://gerrit.libreoffice.org/33629Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>