i#1551 port to ARM: fix bug in mangle_rel_addr
i#1551 port to ARM: fix bug in mangle_rel_addr

Fixes a bug in mangle_rel_addr(): we have to preserve all attributes
(flags, index, etc.) of the memop being replaced.  The old code threw out
the index reg and flags.

Review-URL: https://codereview.appspot.com/201370043

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