LU-10210 tests: Add lustre_routes_conversion script in PATH

LU-10210 tests: Add lustre_routes_conversion script in PATH

When running out of build tree test_67 in conf-sanity.sh cannot
find lustre_routes_conversion script because it's not in PATH.

Add lustre_routes_conversion script in test-framework.sh
init_test_env() so that it is visible when running out of
build tree.

Test-Parameters: trivial testlist=conf-sanity
Change-Id: Id5ed93e0176f0b42aa704511c72fbe14902ea42f
Signed-off-by: Sonia Sharma <sonia.sharma@intel.com>
Reviewed-on: https://review.whamcloud.com/30335
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>