Automatic merge from submit-queue

newCFSSLSigner: improve error reporting by including file name in the message

**What this PR does / why we need it**:

This PR improves error reporting by including an action and a file name into the error message.

Before:
>E0605 17:01:57.020485   29156 certificates.go:38] Failed to start certificate controller: open : no such file or directory

After:
>E0605 18:21:32.375884    4896 certificates.go:38] Failed to start certificate controller: error reading CA file "": open : no such file or directory

**Release note**:
```release-note
NONE
```

CC @mfojtik