tests.guest_suspend: Check SSDT when disabling S4

Changes from V1:
 * Disable RHEL.5.i386 guest for this test since there
   is no iasl package for this platform.
 * Update the cmd for RHEL/Fedora guests separately.
Signed-off-by: NQingtang Zhou <qzhou@redhat.com>

tests/cfg/guest_suspend.cfg

@@ -28,6 +28,8 @@
         - global_disable_s4:
             only guest_s4
             no Host_RHEL.5, Host_RHEL.6.0, Host_RHEL.6.1, Host_RHEL.6.2
+            # The iasl package isn't available on RHEL5 i386 platform.
+            no RHEL.5.i386
             negative_test = yes
             extra_params += " -global PIIX4_PM.disable_s4=1"
         - global_enable_s4: