LU-734 tests: add sub-tests into recovery-*-scale tests

LU-734 tests: add sub-tests into recovery-*-scale tests

This patch adds sub-tests into the recovery-*-scale tests
so that test results and logs could be gathered properly
and uploaded to Maloo.

The patch also does some cleanup works on the test scripts
and moves some common functions into test-framework.sh.

Signed-off-by: Yu Jian <yujian@whamcloud.com>
Change-Id: Ife174285d182ad5a2d4823767ca59df5a10b4aa4
Reviewed-on: http://review.whamcloud.com/2509
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-by: Cliff White <cliffw@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>