LU-1892 osp: Fix Doxygen warnings for osp_trans.c

LU-1892 osp: Fix Doxygen warnings for osp_trans.c

After patch 10361, three Doxygen warnings were created due to
incorrect syntax. This patch fixes those.

Signed-off-by: Doug Oucharek <doug.s.oucharek@intel.com>
Change-Id: Iaaec90f545a8f55522b5f87111dea2b544592ea2
Reviewed-on: http://review.whamcloud.com/12659
Tested-by: Jenkins
Reviewed-by: Richard Henwood <richard.henwood@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>