LU-16183 tests: sanity-hsm/70 should detect python

LU-16183 tests: sanity-hsm/70 should detect python

Check for python2 and python3 explicitly, since the
generic python command does not exist in newer distros.

Test-Parameters: env=SLOW=yes,ENABLE_QUOTA=yes \
clientdistro=sles15sp3 testlist=sanity-hsm
Test-Parameters: env=SLOW=yes,ENABLE_QUOTA=yes \
clientdistro=el7.9 testlist=sanity-hsm
Signed-off-by: Minh Diep <mdiep@whamcloud.com>
Change-Id: I2251be461129310868868277bf9d46015545ffe2
Reviewed-on: https://review.whamcloud.com/48577
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Alex Deiter <alex.deiter@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>