Convert qemu command line flags to 64-bit int

The QEMU flags are commonly stored as a signed or unsigned int,
allowing only 31 flags. This limit is rather close, so to aid
future patches, change it to a 64-bit int

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h, src/qemu/qemu_driver.c,
  tests/qemuargv2xmltest.c, tests/qemuhelptest.c, tests/qemuxml2argvtest.c:
  Use 'unsigned long long' for QEMU flags

tests/qemuargv2xmltest.c

@@ -75,7 +75,7 @@ static int testCompareXMLToArgvFiles(const char *xml,
 
 struct testInfo {
     const char *name;
-    int extraFlags;
+    unsigned long long extraFlags;
     const char *migrateFrom;
 };