Fix RSA certificate key determination. (#602)

* Fix RSA certificate key determination.

Fixes #599.

* Correct serialization of RSA certificates with unlimited dates.

* The test for connecting with RSA certificate.

* Remove redundant change in TransportImpl.java

* Add forgotten test keys.

* Make net.schmizz.sshj.common.KeyType.CertUtils.epochFromDate readable.

Co-authored-by: Vladimir Lagunov <vladimir.lagunov@jetbrains.com>
Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

src/itest/groovy/com/hierynomus/sshj/signature/RsaSignatureClientKeySpec.groovy

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C)2009 - SSHJ Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.hierynomus.sshj.signature
+
+import com.hierynomus.sshj.IntegrationBaseSpec
+import net.schmizz.sshj.DefaultConfig
+import spock.lang.Unroll
+
+class RsaSignatureClientKeySpec extends IntegrationBaseSpec {
+    @Unroll
+    def "should correctly connect using publickey auth with RSA key with signature"() {
+        given:
+        def client = getConnectedClient(new DefaultConfig())
+
+        when:
+        client.authPublickey(USERNAME, "src/itest/resources/keyfiles/id_rsa2")
+
+        then:
+        client.authenticated
+    }
+}