LU-611 tests: clean up code style in tests/lfs

LU-611 tests: clean up code style in tests/lfs

Make existing "lfs {find,getstripe,setstripe}" tests more consistent.
- whitespace/line wrap/line continuation cleanups
- put the options at the start, and pathnames at the end.
- use $GETSTRIPE and $SETSTRIPE everywhere
- use "getstripe [-c|-i|-S]" instead of parsing verbose output
- use "getstripe -S" instead of "getstripe -s"
- replace uses of "getstripe --offset" with "getstripe --index"

Make sanity test_27z parsing of "lfs getstripe" output more robust:
- do not depend on positional parameters for most output
- use "lfs getstripe [-c|-i|-S]" options to get specific values
- parse OST index/objid/seq on a line-by-line basis
- use debugfs to extract filter_fid info instead of unmount/remount OSTs

Remove duplicate code in test_204 parsing of default/raw striping.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Ia90de17e39e38543bcd9bc5a9861533accf6500c
Reviewed-on: http://review.whamcloud.com/2022
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Reviewed-by: Li Wei <liwei@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>