MAINT: Only output errors in C style check
Title is self-explanatory.  Follow-up to #14814.

## [Current coverage](https://codecov.io/gh/pandas-dev/pandas/pull/14924?src=pr) is 84.64% (diff: 100%)
> Merging [#14924](https://codecov.io/gh/pandas-dev/pandas/pull/14924?src=pr) into [master](https://codecov.io/gh/pandas-dev/pandas/branch/master?src=pr) will decrease coverage by **<.01%**

```diff
@@             master     #14924   diff @@
==========================================
  Files           144        144          
  Lines         51019      51019          
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
- Hits          43188      43187     -1   
- Misses         7831       7832     +1   
  Partials          0          0          
```

> Powered by [Codecov](https://codecov.io?src=pr). Last update [39efbbc...40e6e06](https://codecov.io/gh/pandas-dev/pandas/compare/39efbbce6e20a48b37809393714788bf67db8067...40e6e06c258013e5ccfabfade77895696ee4b4d0?src=pr) lgtm. can you also move the pip install cpplint to the top of lint.sh (so it doesn't mess up the output).

ping when pushed. @jreback : Moved `cpplint` install to right after the `if` statement (no need to install if not linting).