BFD/ELF: Correct a `remove' global shadowing error for pre-4.8 GCC

BFD/ELF: Correct a `remove' global shadowing error for pre-4.8 GCC

Remove `-Wshadow' compilation errors:

cc1: warnings being treated as errors
.../bfd/elflink.c: In function 'bfd_elf_final_link':
.../bfd/elflink.c:11722: error: declaration of 'remove' shadows a global declaration
/usr/include/stdio.h:154: error: shadowed declaration is here

which for versions of GCC before 4.8 prevent support for ELF targets
from being built.  See also GCC PR c/53066.

	bfd/
	* elflink.c (bfd_elf_final_link): Rename `remove' local variable
	to `remove_section'.