[DLM] Fix potential conflict in DLM userland locks

Just spotted this one. The lockinfo structs are hashed by lockid but into a
global structure. So that if there are two lockspaces with the same lockid all
hell breaks loose. I'm not exactly sure what will happen but it can't be good!

The attached patch moves the lockinfo_idr into the user_ls structure so that
lockids are localised.

patrick

Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>