Ensure that ssh authentication is retried only in JGit

JGit wants to control retries during ssh authentication. But JSch by
default already retries 6 times. Hence disable retries in JSch. Without
this the credentials provider isn't reset if e.g. wrong credentials are
specified.

Bug: 430210
Change-Id: I6fa726a14a84b06411e7010608c7a1e2bfb8bfe8

org.eclipse.jgit/src/org/eclipse/jgit/transport/JschConfigSessionFactory.java

@@ -148,6 +148,9 @@ public abstract class JschConfigSessionFactory extends SshSessionFactory {
 			FS fs, String user, final String pass, String host, int port,
 			final OpenSshConfig.Host hc) throws JSchException {
 		final Session session = createSession(hc, user, host, port, fs);
+		// We retry already in getSession() method. JSch must not retry
+		// on its own.
+		session.setConfig("MaxAuthTries", "1"); //$NON-NLS-1$ //$NON-NLS-2$
 		if (pass != null)
 			session.setPassword(pass);
 		final String strictHostKeyCheckingPolicy = hc