[PATCH] Revert the lsda change to scan_eh_tab.

[Logan Chien]

Hi Albert,

IMO, we can simply use #ifdef to provide different code for ARM EHABI.

There should be similar problem with _Unwind_GetRegionStart(), and I feel
it will be
less straightforward to introduce more and more arguments to scan_eh_tab().

Sincerely,
Logan

http://reviews.llvm.org/D4326