LU-4953 lprocfs: fix missing target_obds on multiple mounts

LU-4953 lprocfs: fix missing target_obds on multiple mounts

In the case of multiple mountes the target_obds only showed
up for the first mount. The reason for this was that we were
using procsym in obd_type to hold the pointer to the
proc_dir_entry for target_obds. But obd_type is shared across
all lmv/lov object instances. Instead we need to cache the
proc_dir_entry in the private data structure; lov_obd and
lmv_obd; for each type of obd device impacted. Later these
handles will be used for cleanup when the module unloads.

Change-Id: Idf7a78f9ca662af78c217bb1142409b9b0322192
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Reviewed-on: http://review.whamcloud.com/10192
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>