libbpf-tools: fix an error message
libbpf-tools: fix an error message

A wrong argument (-errno) was passed to strerror, fix it.

Signed-off-by: Anton Protopopov <73889760778ff960467ba75991d0ae67a00c37ec@gmail.com>

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