Segmentation fault in unit test due to SILKRPC_LOG trace

[canepat]

Adding one or more SILKRPC_LOG traces causes the unit test executable to crash with segmentation fault

Probably it's something related to logging streams, please @Sixtysixter provide more info here when available

[Sixtysixter]

The log instance responsible for logging is teestream, instantiated by default with std::cerr stream and a null stream (see https://github.com/torquem-ch/silkrpc/blob/ee585804b3d8a7916b6ea8df01ea08a3b662d047/silkrpc/common/log.cpp#L33 ).
The internal pointers to std::streambuf are initialized calling rdbuf() on
The rdbuf() call on std:cerr, used in this way, returns a pointer that seem bad (at 0x7ffff....).
This cause the segmentation violation fail (both with gcc and clang).
It is need to add
SILKRPC_LOG_STREAMS(null_stream(), null_stream());
to properly set the log instance.
Note that the crash happens if the tested code contains some trace allowed by the verbosity level (ie SILKRPC_LOG) so set the verbosity to NONE is not enough (by default it is set to INFO)