transports: ssh: ask for credentials again when passphrase is wrong

When trying to decode the private key it looks like LibSSH2 returns a
LIBSSH2_ERROR_PUBLICKEY_UNVERIFIED when the passphrase is incorrect.

src/transports/ssh.c

@@ -419,7 +419,9 @@ static int _git_ssh_authenticate_session(
 		}
 	} while (LIBSSH2_ERROR_EAGAIN == rc || LIBSSH2_ERROR_TIMEOUT == rc);
 
-        if (rc == LIBSSH2_ERROR_PASSWORD_EXPIRED || rc == LIBSSH2_ERROR_AUTHENTICATION_FAILED)
+	if (rc == LIBSSH2_ERROR_PASSWORD_EXPIRED ||
+		rc == LIBSSH2_ERROR_AUTHENTICATION_FAILED ||
+		rc == LIBSSH2_ERROR_PUBLICKEY_UNVERIFIED)
 			return GIT_EAUTH;
 
 	if (rc != LIBSSH2_ERROR_NONE) {