Handle newlines better in sslerrorprinter.cpp
Handle newlines better in sslerrorprinter.cpp

According to https://github.com/openssl/openssl/blob/4cedf30e995f9789cf6bb103e248d33285a84067/crypto/err/err_prn.c#L20
the ERR_print_errors_cb function already adds newlines to the end
of each line. So we can just append right away. We do remove the
last newline as normally error messages don't end with a newline.
Also we may return 0 instead of 1.

CopernicaMarketingSoftware/AMQP-CPP,CopernicaMarketingSoftware/AMQP-CPP