Reduce file permissions in y.go (#1056)
Reduce file permissions in y.go (#1056)

one of the issues listed in
https://deepsource.io/gh/jaipradeesh/badger/issues/ is excessive
permissions. The functions in y.go are opening files with 0666
permissions. This PR changes them to 0600 for improved security.
dgraph-io/badger,dgraph-io/badger