ViewCert: clean up Qt 4/Qt 5 compatibility code.
ViewCert: clean up Qt 4/Qt 5 compatibility code.

The previous code assumed that each subject info
item only happens once. That was true for Qt 4, but
in Qt 5, QSslCertificate::subjectInfo() and
QSslCertificate::issuerInfo() return a QStringList.

This commit updates ViewCert to be able to show
multiple occurrences of each item.

Lartza/mumble,SuperNascher/mumble,Lartza/mumble,SuperNascher/mumble,Lartza/mumble,LuAPi/mumble,LuAPi/mumble,Lartza/mumble,SuperNascher/mumble,SuperNascher/mumble,LuAPi/mumble,LuAPi/mumble,Lartza/mumble,LuAPi/mumble,SuperNascher/mumble,SuperNascher/mumble,Lartza/mumble,SuperNascher/mumble,Lartza/mumble,LuAPi/mumble,SuperNascher/mumble,LuAPi/mumble,LuAPi/mumble,Lartza/mumble,LuAPi/mumble,SuperNascher/mumble