Fix missing OOM check in qemuParseCommandLine when splitting strings

The qemuParseCommandLine method did not check the return value of
virStringSplit to see if OOM had occurred. This lead to dereference
of a NULL pointer on OOM.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/qemu/qemu_command.c

@@ -11387,7 +11387,8 @@ qemuParseCommandLine(virCapsPtr qemuCaps,
              * Set os.machine only if first parameter lacks '=' or
              * contains explicit type='...' */
             WANT_VALUE();
-            list = virStringSplit(val, ",", 0);
+            if (!(list = virStringSplit(val, ",", 0)))
+                goto error;
             param = list[0];
 
             if (STRPREFIX(param, "type="))