LU-8434 tests: add script language option to auster

LU-8434 tests: add script language option to auster

auster is a scipt that kicks off the Lustre test suites.
auster assumes that all scirpts are written in bash and
runs all script using bash. We may want to run other scripts
to test Lustre and we need to allow the user to choose what
scripting language to use to kick off their scripts.

Test-Parameters: trivial

Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: Ifbd3707171de57912306cf051a98922249c4b2a9
Reviewed-on: https://review.whamcloud.com/34737
Tested-by: Jenkins
Reviewed-by: Joseph Gmitter <jgmitter@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>