Fix: illegal memory access in output_init

Fix: illegal memory access in output_init

Found by Coverity:

CID 1243028 (#1 of 2): Buffer not null terminated
(BUFFER_SIZE_WARNING)5. buffer_size_warning: Calling strncpy with a
maximum size argument of 255 bytes on destination array output->name of
size 255 bytes might leave the destination string unterminated.

CID 1243028 (#2 of 2): Buffer not null terminated
(BUFFER_SIZE_WARNING)10. buffer_size_warning: Calling strncpy with a
maximum size argument of 4096 bytes on destination array
output->consumer->dst.trace_path of size 4096 bytes might leave the
destination string unterminated.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>