LU-4647 tests: clean up sanity-sec code style issues

Minor cleanups in sanity-sec coding style seen during code review:
- fix indentation to use tabs
- don't continue strings with open quotes (adds indent to string)
- remove unnecessary linefeed escapes
- replace subshells with backquotes `...` to use $(...)

Remove no-op test_3(), as it is superceded by nodemaps.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: If96e3ddee723747987ca5309e982e36af202fb26
Reviewed-on: http://review.whamcloud.com/14769
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Tested-by: Jenkins
Reviewed-by: James Nunez <james.a.nunez@intel.com>