seal pre commit(2) in case miner and remote worker have same directory

[ldoublewood]

Describe the bug
seal pre commit(2) in case miner and remote worker have same directory

To Reproduce
Steps to reproduce the behavior:

1. Run miner and a remote worker as a private network
2. IMPORTANT: miner and remote worker use different directory, e.g. /home/miner for miner, /home/worker for worker
3. Run "sector pledge" in miner
4. Check worker log and run "sectors list"
5. See PreCommitFail in sectors list and disappear after a while
6. See the following log in worker
   2020-03-31T10:51:59.971+0800 WARN sectors sealing/fsm.go:288 sector 9 got error event sealing.SectorSealFailed: seal pre commit(2) failed: presealing sector 9 (): Missing store file: /home/miner/.lotusworker/cache/s-t01007-9/sc-02-data-layer-1.dat

Expected behavior
No error message and no Fail in sector list

Screenshots

Version (run lotus --version):
testnet/3, f2d90b8

Additional context

[magik6k]

This is now fixed