Tor warns about config abbreviations every time a controller does an ambiguous getconf

The torrc and GETCONF accepts command abbreviations (for instance "ControlPo" instead of "ControlPort"). This was a mistake since it results in ambiguity for similarly named commands (for instance does "Socks" match "SocksPort" or "SocksBindAddress"?). Hence, use of this is discouraged and results in a warning.

Warnings are emitted in the 'expand_abbrev' function of 'or/config.c' (line 1353). The problem is that this is a getter function, called for a variety of purposes like GETCONF. This means that controllers may accidentally spam users with warnings by requesting an alias repeatedly.

In my opinion the proper handling of this is to either remember the warnings we've given (avoiding duplication), or even better to just provide warnings when reading in the torrc. Cheers! -Damian