ut：meta server core，when recovery debug ut execute

[GehaFearless]

after ./run.sh test on type debug system program，I failed at recovery test.

meta server core msg

And then I add some message logs，I find field "duplicating" on struct app_info is null when I create a table.I am not sure what happened between create table and recovery, But I think the initial value should be false.
After set "duplicating"=false for app_info on file rdsn/src/dsn.layer2.thrift, ut passed.
diff struct app_info init code:

[hycdong]

Thanks for your nice work~ How about raise a pull request to fix this problem?

[levy5307]

Fixed at XiaoMi/rdsn#976