"filer.remote.gateway" should ignore the .part file in the .upload directory

[imfantuan]

Describe the bug
I1214 01:55:49 16266 filer_remote_gateway_buckets.go:205] create backends3/some_bucket/.uploads/d9bea775-f8c5-43aa-a4c9-3a65c10f0024/0001.part

System Setup

weed filer.remote.gateway -createBucketWithRandomSuffix=false -filerProxy -createBucketAt=backends3

Expected behavior
Ignore these "xxxx.part" file.

[imfantuan]

still many delete & rmdir "/.upload/" logs

I1219 14:39:40 64797 filer_remote_gateway_buckets.go:237] delete backendweed/localbucket/.uploads/f53bb1b6-6c3f-4e1a-abbb-649799acc2de/0001.part
I1219 14:39:40 64797 filer_remote_gateway_buckets.go:237] delete backendweed/localbucket/.uploads/f53bb1b6-6c3f-4e1a-abbb-649799acc2de/0001.part
I1219 14:39:40 64797 filer_remote_gateway_buckets.go:237] delete backendweed/localbucket/.uploads/f53bb1b6-6c3f-4e1a-abbb-649799acc2de/0002.part
I1219 14:39:40 64797 filer_remote_gateway_buckets.go:237] delete backendweed/localbucket/.uploads/f53bb1b6-6c3f-4e1a-abbb-649799acc2de/0002.part
I1219 14:39:40 64797 filer_remote_gateway_buckets.go:234] rmdir  backendweed/localbucket/.uploads/f53bb1b6-6c3f-4e1a-abbb-649799acc2de
I1219 14:39:40 64797 filer_remote_gateway_buckets.go:234] rmdir  backendweed/localbucket/.uploads/f53bb1b6-6c3f-4e1a-abbb-649799acc2de
I1219 14:39:40 64797 filer_remote_gateway_buckets.go:234] rmdir  backendweed/localbucket/.uploads/f53bb1b6-6c3f-4e1a-abbb-649799acc2de
I1219 14:39:40 64797 filer_remote_gateway_buckets.go:234] rmdir  backendweed/localbucket/.uploads/f53bb1b6-6c3f-4e1a-abbb-649799acc2de