Fix build with Ossim >= 2.8

There was a lot of missing std:: in OssimPlugins. I assume they were hidden by a using namespace std in a ossim header.

This may need to be backported in the 6.6 branch for packaging on Debian.

changed milestone to %7.0.0

added bug label

Linked with #1943 (closed)

merged

mentioned in commit 4ffb954d