OIDC plugin installation fails behind HTTP proxy

[Cantor, Scott]

I just tested this, proxying it works fine.

    <bean id="myHttpClient" parent="shibboleth.HttpClientFactory"
        p:connectionProxyHost="redacted"
        p:connectionProxyPort="80" />

Command was just idp/bin/plugin.sh -hc myHttpClient <pluginfile> ./beanfile.xml

-- Scott