zdtm: It's need turn off FORTIFY_SOURCE instead of use -Wno-unused-result option

The -Wno-unused-result option looks to have been introduced in GCC 4.5.0.
So it's need turn off FORTIFY_SOURCE (compiler warn about unused results
in fortification mode) instead of use -Wno-unused-result to avoid error
in versions prior to 4.5.0.
Signed-off-by: Victor Konyashkin  <vkonyashkin@parallels.com>
Acked-by: Andrey Wagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm/lib/Makefile

-CFLAGS	= -g -O2 -Wall -Werror -Wno-unused-result
+CFLAGS	= -g -O2 -Wall -Werror -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0
 
 LIB	= libzdtmtst.a
 

test/zdtm/live/static/Makefile

 LIBDIR	= ../../lib
 LIB	= $(LIBDIR)/libzdtmtst.a
 override CPPFLAGS += -I$(LIBDIR)
-CFLAGS	= -g -O2 -Wall -Werror -Wno-unused-result
+CFLAGS	= -g -O2 -Wall -Werror -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0
 
 TST_NOFILE	=				\
 		busyloop00			\