Do not print to stderr if user specified log buffer
Do not print to stderr if user specified log buffer

iovisor/bcc,mcaleavya/bcc,mcaleavya/bcc,brendangregg/bcc,tuxology/bcc,iovisor/bcc,iovisor/bcc,mcaleavya/bcc,tuxology/bcc,brendangregg/bcc,mcaleavya/bcc,mcaleavya/bcc,iovisor/bcc,brendangregg/bcc,tuxology/bcc,tuxology/bcc,brendangregg/bcc,tuxology/bcc,iovisor/bcc,brendangregg/bcc