LU-4689 hsm: count NULL terminator in hai_first/hal_size

LU-4689 hsm: count NULL terminator in hai_first/hal_size

If fsname is 8-byte aligned, hai_first fails to count the ending NULL
terminator causing hai to directly attached after fsname and future
hai_first will return a different position for first hai.

Signed-off-by: Peng Tao <bergwolf@gmail.com>
Change-Id: I5e9e1f48f99b4743b2d5b93397e06f6becabeb26
Reviewed-on: http://review.whamcloud.com/9431
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>