Fix: Use PERROR all across lttng-tools, never make it quiet

We never want to hide these errors, even in quiet mode. For those
"errors" that are expected and part of the normal operation (e.g. send
consumer channel: Socket operation on non-socket), we will have to
handle the return values and errno explicitly in the code.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>