Add the ability to advertise an attribute in the entry classad also if constant
Attributes are designed to be used in the glidein.
So there is no explicit flag to advertise them in the classad (glidefactory) that is used to communicate w/ the Frontend.
They are added there if they are not constant and can be modified by the Frontend.
They may be useful for the Entry selection query in the Frontend groups or in the match expression.
An attribute should be added to specify if the attr should be published or not in the classad.
Off course if the attr is not constant it will be published anyway.
NOTE: in adding the attribute check that the presence of the attribute in the classad is not interpreted automatically in the frontend as being able to modify it