Add check_path()

[WenjieDu]

What does this PR do?

1. adding tsdb.utils.file.check_path();

Before submitting

• [x] This PR is made to fix a typo or improve the docs (you can dismiss the other checks if this is the case).
• [x] Was this discussed/approved via a GitHub issue? Please add a link to it if that's the case.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] I have written necessary tests and already run them locally.

[coveralls]

Pull Request Test Coverage Report for Build 9708255707

Details

• 22 of 25 (88.0%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.02%) to 82.939%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
tsdb/utils/file.py	22	25	88.0%
<!--	Total:	22	25	88.0%	-->

Files with Coverage Reduction	New Missed Lines	%
tsdb/utils/file.py	1	74.16%
<!--	Total:	1		-->

Totals
Change from base Build 9707011964:	-0.02%
Covered Lines:	491
Relevant Lines:	592

---

💛 - Coveralls