Fix nat/linux-personality.c regression on RHEL-5

Fix nat/linux-personality.c regression on RHEL-5

This commit fixes the regression on RHEL-5 systems introduced by
nat/linux-personality.c's check of HAVE_DECL_ADDR_NO_RANDOMIZE.
RHEL-5 systems define HAVE_DECL_ADDR_NO_RANDOMIZE as zero, so we
cannot use #ifndef; instead this patch uses the "#if !" construction.

The regression was reported by Ulrich Weigand here:

  <https://sourceware.org/ml/gdb-patches/2015-01/msg00458.html>

gdb/ChangeLog
2015-01-16  Sergio Durigan Junior  <sergiodj@redhat.com>

	* nat/linux-personality.c: Replace "#ifndef
	HAVE_DECL_ADDR_NO_RANDOMIZE" by "#if
	!HAVE_DECL_ADDR_NO_RANDOMIZE", fixing a regression in RHEL-5
	systems.