LU-6142 tests: Use correct target/d* name under init_src

LU-6142 tests: Use correct target/d* name under init_src

This patch fixes init_src() calling /tmp/target/d*
with incorrect filename.

Test-Parameters: trivial testlist=lustre-rsync-test
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: Iac5865b3b232e5897eba5ac994fa318ecb35d2d5
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56565
Reviewed-by: Alex Deiter <adeiter@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>