[ELF][fix] Using statically linked lld leads to segmentation fault on linking ELF

[Synopsys]
Using function elf::link(...) leads to segmentation fault on its second call. First call finishes correctly.
[Solution]
Clear the rest of globals.

Reviewed by: George Rimar and Rui Ueyama

Differential Revision: http://reviews.llvm.org/D38131

llvm-svn: 314108