log/linux: make default output stderr

log/linux: make default output stderr

In Linux by default DPDK log goes to stdout, as well as syslog.

It is possible for an application to change the library output stream
via 'rte_openlog_stream()' API, to set it to stderr, it can be used as:
rte_openlog_stream(stderr);

But still updating the default log output to 'stderr'.

Bugzilla ID: 8
Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org
Reported-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com>
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>