5  0x00002aaab055f81e in rtl::OUString::copy (this=0x7fffffff29d0, beginIndex=3, count=-4) at /home/julien/lo/libreoffice/include/rtl/ustring.hxx:2223
6  0x00002aaab070acd2 in (anonymous namespace)::GetContentPart (_rRawString="CN=timur.davletshin@gmail.com", _rPartId="CN")
    at /home/julien/lo/libreoffice/sfx2/source/dialog/dinfdlg.cxx:748
7  0x00002aaab070dd85 in SfxDocumentPage::ImplUpdateSignatures (this=0x55555ca2e0b0) at /home/julien/lo/libreoffice/sfx2/source/dialog/dinfdlg.cxx:901

so do the same as GetContentPart from uui/source/secmacrowarnings.cxx
(I suppose we should avoid the redundancy but that's another story)

Change-Id: Ief3ce1cce7035fb572778bdee02a1073b7dfe1c1
Reviewed-on: https://gerrit.libreoffice.org/32530Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>