Initializing OpenSSHKeyV1KeyFile does not use correct publicKey for null check

[katjas]

Hi there, there is an issue in the init method of OpenSSHKeyV1KeyFile - it'0s checking the "pubKey" on null, instead of the "publicKey" which is passed to the method. Like this, the pubKey stays null always. Thanks for checking, Katja

https://github.com/hierynomus/sshj/blob/31ed35407cf04b1781119e7ee5a99c9157f3cd86/src/main/java/com/hierynomus/sshj/userauth/keyprovider/OpenSSHKeyV1KeyFile.java#L124

[dkocher]

In #944.

[dkocher]

Duplicate for #907.