Improve message output from run-step.sh
Improve message output from run-step.sh

run-step prints a message to tell the reader what it's doing. However,
that message wasn't flushed so that run-step could print OK or FAILED on
the same line. The result was that long-running steps wouldn't print
anything to the log until they were done, at least in Jenkins contexts.

This patch changes it so that the message is flushed, and then the
result is printed on a separate line (including the time it took to run
the step).

  $ run-step "Hello world!" helloworld.out sleep 5
  Hello world! (logging to /tmp/helloworld.out)...
      OK (Took: 0 min 5 sec)

Change-Id: Iaced729f0ef6aa93174cd90b1516d3c34fe41a22
Reviewed-on: http://gerrit.cloudera.org:8080/5116
Reviewed-by: Alex Behm <fe1626037acfc2dc542d2aa723a6d14f2464a20c@cloudera.com>
Tested-by: Internal Jenkins

cloudera/Impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,cloudera/Impala,cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala