Connector should explicitly disable certificate verification if application does not selects otherwise

Both version series are built on top of C/C 3.3, but we do not disable linking against C/C 3.4. The main and actually only incompatibility between 3.3 and 3.4 is that 3.4 enables certificate verification by default. In C/C++ it is disabled by default, but it does not turn it off explicitly, relying on C/C's default and that is not quite right thing to do anyway.