XrdSecgsi vomsat and vomsfun don't behave as documented

[esindril]

Hi,

While trying to enable the extraction of the VOMS attributes from certificates for gsi authentication, from the documentation it seems that setting the vomsat to extract should be sufficient to also enable the vomsfun to be set to default.
https://xrootd.slac.stanford.edu/doc/dev54/sec_config.htm#_Toc79101994
More precisely the last statement in the documentation snippet below is not reflected in the code:

vomsfun: {file|default}
            specifies the location of the voms plug-in:
            file  -   is the full path if a shared library containing a plug-in function to be called to extract information from the VOMS certificate extension;
            default  -  use the default [extractor](https://xrootd.slac.stanford.edu/doc/dev54/sec_config.htm#_The_voms_plug-in) that comes with the gsi package.

Default is default when the extract or require option is in effect.

Therefore, to have things working one needs to specify both vomsat and vomsfun. Therefore, either the documentation should be updated to reflect the current situation or the code needs to be fixed to have vomsfun set to default if vomsat is enabled.
Using XRootD 5.5.1.

Thanks!