Fix OSError in postprocess

Wrong order of clearing LibvirtdDebugLogConfig causes OSError.

Signed-off-by: lcheng <[email protected]>

virttest/env_process.py

@@ -1041,13 +1041,13 @@ def preprocess(test, params, env):
     _setup_manager.register(CheckInstalledCMDs)
     _setup_manager.register(UlimitConfig)
     _setup_manager.register(NetworkProxies)
-    _setup_manager.register(LibvirtdDebugLogConfig)
     _setup_manager.register(BridgeConfig)
     _setup_manager.register(StorageConfig)
     _setup_manager.register(FirewalldService)
     _setup_manager.register(IPSniffer)
     _setup_manager.register(MigrationEnvSetup)
     _setup_manager.register(UnrequestedVMHandler)
+    _setup_manager.register(LibvirtdDebugLogConfig)
     _setup_manager.do_setup()
 
     vm_type = params.get("vm_type")