LU-5066 build: fix compile issues with newer gcc

LU-5066 build: fix compile issues with newer gcc

Fixed the error: 'name' may be used uninitialized in
the osd_compact code. Also added padding to struct
shrinker for the posix layer otherwise gcc complies
it away and we end up with a build failure.

Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I164957525d572d9d7a58196e5b38fb1349745d44
Reviewed-on: http://review.whamcloud.com/9678
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Tested-by: Jenkins
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>