Get rid of probe_geometry_columns (typmod support)

[robe]

All this function did was to inspect the geometry_columns table and notify of stale entries and add missing entries.

Now that geometry_columns will be a view in 2.0, this function is completely irrelevant.

We hadn't marked it for deprecation, but it seems necessary to completely remove it or keep it and have it do nothing except to show a notice that says:

"I do not do anything anymore, get with the program"

I'd just assume drop the function entirely