fixes issue 1028
fixes issue 1028

In dr_mark_trace_head(), acquire shared linking lock up front (even
when not needed) to satisfy rank order requirements.

SVN-Revision: 1791

bl4ckic3/dynamorio,bl4ckic3/dynamorio,code4bones/dynamorio,sigma-random/dynamorio,AmesianX/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,bl4ckic3/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,AmesianX/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,daksunt/dynamorio,bl4ckic3/dynamorio,code4bones/dynamorio,daksunt/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,daksunt/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,code4bones/dynamorio,bl4ckic3/dynamorio