LU-11010 tests: remove calls to return after skip()

LU-11010 tests: remove calls to return after skip()

The skip routine now contains a call to exit. All calls
to skip() and skip_env() should be reviewed and calls to
return() that follow skip() should be removed.

This is the third patch in a series that removes calls
to return() after skip() in the Lustre test suites.

Calls to return after skip() are removed for:
large-lun.sh
large-scale.sh
lfsck-performance.sh
lnet-selftest.sh
lustre-rsync-test.sh
mds-survey.sh
metadata-updates.sh

Test-Parameters: trivial testlist=large-lun,large-scale,lfsck-performance,lnet-selftest,lustre-rsync-test,mds-survey,metadata-updates

Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: Id11dc4bbde5824976a5a4d8f94ea59efd45e46f4
Reviewed-on: https://review.whamcloud.com/32732
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>