readelf: tidy dump_relr_relocations

A comment in display_relocations said "RELRS has been freed by
dump_relr_relocations".  Except that hadn't happened on all return
paths.  Tidy that by freeing relrs allocated in dump_relr_relocations
in that function, and relrs allocated in display_relocation in that
function.

	* readelf.c (dump_relr_relocations): Only free relrs allocated
	in this function.
	(display_relocations): Free relrs here, on error return paths
	too.