IMPALA-1349: Redirect stdout/stderr to INFO/ERROR log.

This patch adds a flag (on by default) to redirect stdout/stderr to INFO/ERROR
logs. Components we link (e.g., llvm, hdfs) log to stderr and having the logs
in one place is very helpful.

Change-Id: Ib29fddde5843311bfa099a70a0e8ba5d726c8bce
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/5240
Tested-by: jenkins
Reviewed-by: Nong Li <nong@cloudera.com>