LU-7479 tests: fix lustre-rsync-test test_2a on SLES12

LU-7479 tests: fix lustre-rsync-test test_2a on SLES12

In sles12, ldd output has a wrong format for linux-vdso.so.1.
Since it is a virtual file so strip out is reasonable.

Signed-off-by: Yang Sheng <yang.sheng@intel.com>
Change-Id: I335139c4278db771a0c313573dde41eb9b96d649
Reviewed-on: http://review.whamcloud.com/17475
Tested-by: Jenkins
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>