Revert "automake: Don't fail the build if we can't setuid."

This reverts commit e7ad5cdcd2.

If you ask for setuid install and that fails you didn't get what you
asked for and we shouldn't just silently carry on.  If installing weston
somewhere in your home directory and don't want the setuid bit set,
disable that at configure time.

src/Makefile.am

@@ -26,8 +26,8 @@ weston_SOURCES =			\
 
 if ENABLE_SETUID_INSTALL
 install-exec-hook:
-	-chown root $(DESTDIR)$(bindir)/weston
-	-chmod u+s $(DESTDIR)$(bindir)/weston
+	chown root $(DESTDIR)$(bindir)/weston
+	chmod u+s $(DESTDIR)$(bindir)/weston
 endif
 
 if ENABLE_XSERVER_LAUNCHER