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: I2c23b641e62a56882171982b8a3157ba023ea36c
Reviewed-on: http://review.whamcloud.com/2265
Tested-by: Hudson
Reviewed-by: Cliff White <cliffw@whamcloud.com>
Reviewed-by: Minh Diep <mdiep@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>