qemu_conf: Undefine the correct symbol

At the beginning of the qemu config file parsing function there
are 3 helper macros defined: GET_VALUE_BOOL, GET_VALUE_LONG and
GET_VALUE_STR. Later, when they are no longer needed they are
undefined in order to keep the namespace clean. However, the
GET_VALUE_STRING is undefined instead of GET_VALUE_STR.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_conf.c

@@ -662,7 +662,7 @@ int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg,
 }
 #undef GET_VALUE_BOOL
 #undef GET_VALUE_LONG
-#undef GET_VALUE_STRING
+#undef GET_VALUE_STR
 
 virQEMUDriverConfigPtr virQEMUDriverGetConfig(virQEMUDriverPtr driver)
 {