etcdserver: snapNames() should exclude orphaned defragmentation file

[tedyu]

In Snapshotter#snapNames(), cleanupSnapdir(names) may clean up orphaned defragmentation file(s).
Such files should be excluded from checkSuffix() call.

[gyuho]

can you rebase?

[codecov-io]

Codecov Report

Merging #11900 into master will increase coverage by 0.04%.
The diff coverage is 58.33%.

@@            Coverage Diff             @@
##           master   #11900      +/-   ##
==========================================
+ Coverage   66.11%   66.15%   +0.04%     
==========================================
  Files         403      403              
  Lines       37165    37170       +5     
==========================================
+ Hits        24571    24591      +20     
- Misses      11067    11069       +2     
+ Partials     1527     1510      -17     

Impacted Files	Coverage Δ
etcdserver/api/snap/snapshotter.go	68.18% <58.33%> (+0.39%)	⬆️
pkg/transport/timeout_conn.go	60.00% <0.00%> (-20.00%)	⬇️
auth/store.go	52.38% <0.00%> (-19.25%)	⬇️
etcdserver/api/v3rpc/lease.go	74.68% <0.00%> (-5.07%)	⬇️
clientv3/leasing/txn.go	88.09% <0.00%> (-3.18%)	⬇️
proxy/grpcproxy/watch.go	89.94% <0.00%> (-1.78%)	⬇️
etcdserver/cluster_util.go	64.18% <0.00%> (-0.94%)	⬇️
mvcc/watchable_store.go	84.75% <0.00%> (-0.36%)	⬇️
clientv3/leasing/kv.go	90.36% <0.00%> (-0.34%)	⬇️
etcdserver/server.go	75.69% <0.00%> (-0.16%)	⬇️
... and 14 more

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[tedyu]

Some test failed:
https://travis-ci.com/github/etcd-io/etcd/jobs/335833989

(the above is allowed to fail)

@gyuho
Do you know where I can find etcdserver log for the failed test ?

Thanks