execstack-0.5.0-bp155.3.11

- fix package description
- update copyright
- cleanup regarding recommendations from spec-cleaner

- add Conflicts with prelink package
  and fix rpmlint warnings need commented macros with double %%

- remove autosetup in spec as source_validator reporting error

- new prelink_add_no_execstack_for_ppc64.patch
  to bypass for ppc64 archi the gcc linker that do not set
  a GNU_STACK header in generated elf file.

- Init new execstack package: (similar to fedora)
  This package is built from prelink sources but contains just the
  execstack binary. It can be used manipulate ELF binaries to run
  with or without executable stack.