[PATCH] Fix the ld flags not be applied to tst-execstack-mod.so

[Florian Weimer]

* Zong Li:

> The Makefile variable name loses the file extension (.so). It causes
> the linker option not applies to the corresponding file that it's
> file name matchs with the variable without LDFLAGS- prefix.
>
> 	* elf/Makefile (LDFLAGS-tst-execstack-mod): Change variable name by
> 	adding the file extension (.so).

This looks okay to me.  Can you commit this yourself, or do you need
someone who commits it for you?

Thanks,
Florian