LU-15479 tests: clean up sanity test_316/test_319

LU-15479 tests: clean up sanity test_316/test_319

These tests use the deprecated "lfs mv" insted of "lfs migrate".

Fix test_316 to specify which MDT to create 'd' on, so MDT space
balancing does not result in 'd' being created on MDT0001, which
defeats the purpose of the test trying to migrate it to MDT0001.

Fix test_319 to call "lfs migrate" on the parent directory and
not on the test file, since this returns an "ENOTDIR" error.

Also fix some minor script style issues.

Test-Parameters: trivial testlist=sanity env=ONLY="316 319",ONLY_REPEAT=100 mdscount=2 mdtcount=4
Test-Parameters: fstype=zfs testlist=sanity env=ONLY="316 319",ONLY_REPEAT=100 mdscount=2 mdtcount=4
Fixes: ae7ca90713b4 ("LU-11926 ldlm: Lost lease lock on migrate error")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I08d55ce70cbd900c2f4d31b27baa1a33423ebbe5
Reviewed-on: https://review.whamcloud.com/46959
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>