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: I514143e1fa29aad289d215174dbc68d2740da73b
Reviewed-on: http://review.whamcloud.com/2508
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: Johann Lombardi <johann@whamcloud.com>