add error message when Gaussian input orientation is missing

[njzjz]

Fix #512.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (f2d09a5) 82.84% compared to head (bb78278) 82.85%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## devel #568 +/- ## ========================================== + Coverage 82.84% 82.85% +0.01% ========================================== Files 74 74 Lines 6591 6595 +4 ========================================== + Hits 5460 5464 +4 Misses 1131 1131 ``` | [Files](https://app.codecov.io/gh/deepmodeling/dpdata/pull/568?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deepmodeling) | Coverage Δ | | |---|---|---| | [dpdata/gaussian/log.py](https://app.codecov.io/gh/deepmodeling/dpdata/pull/568?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=deepmodeling#diff-ZHBkYXRhL2dhdXNzaWFuL2xvZy5weQ==) | `100.00% <100.00%> (ø)` | |

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