mysqlbinlog: unknown variable ssl_key or ssl_cert or ssl_ca I am trying to recover binlog from a remote server using mysqlbinlog client program, however it appears that mysqlbinlog doesn't recognize the SSL options that's required to establish SSL connect to MySQL version 5.5 server, which is set to require X509.

Any other ways to get mysqlbinlog to connect?

Update: I've noticed this bug report from MySQL: https://bugs.mysql.com/bug.php?id=74864

And I've tried use --loose prefix for the 3 SSL options to connect. Still don't work. 

Update: I am running Google Cloud SQL (a hosted version of MySQL 5.5, potentially tweaked by Google, running in Google Cloud), no other access except using MySQL client and via Google Cloud Dashboard to tweak only a few limited parameters.

This is in fact the same limitation for RDS in Amazon Cloud (AWS). The differences is that RDS have option to select MySQL minor versions whereas Google Cloud SQL doesn't allow you to choose a minor version, only 5.5 or 5.6 are available.
BOTTOM OF THE BUG REPORT YOU REFERENCED

[21 Jan 16:44] David Moss
Thanks for your feedback. This was fixed in version 5.7.3, and the following text was added to the 5.7.3 release notes: Previous versions of mysqlbinlog did not correctly accept the ssl-ca option in an option file. This fix ensures that this option can be correctly used. In earlier versions a work around is to use the loose-ssl-ca option.
[19 Feb 16:08] David Moss
Posted by developer:
This was covered in the release notes. Closing.
[27 Feb 9:02] Christoph Mitasch
will this also be fixed for the 5.6.X release?

MySQL 5.6 Documentation
The --ssl-crl and --ssl-crlpath variables were first introduced for mysqlbinlog in MySQL 5.6.3. Once MySQL 5.6 went GA, those options were not meant to be used at all. How did I know ? Look at the list of options for mysqlbinlog (Table 4.16). They appear in the list between --socket and --start-datetime=datetime BUT THEY HAVE NO HYPERLINKS !!!
mysqlbinlog
Here is something else to consider: mysqlbinlog is not a client program. It is a utility program. In mysql, client programs require logging into mysqld with a username and password.
If you look at the list of MySQL Client Programs, please note that mysqlbinlog is not there because it is a utility. You can see mysqlbinlog among the list of MySQL Administrative and Utility Programs.
If you are using an option file, mysqlbinlog can never respond to the options under the [client] group header. Why ? According to the Options File Documentation:

The [client] option group is read by all client programs (but not by mysqld). This enables you to specify options that apply to all clients. For example, [client] is the perfect group to use to specify the password that you use to connect to the server. (But make sure that the option file is readable and writable only by yourself, so that other people cannot find out your password.) Be sure not to put an option in the [client] group unless it is recognized by all client programs that you use. Programs that do not understand the option quit after displaying an error message if you try to run them.

SUGGESTION
I don't know if you will encounter the bug with my suggestion, but here it goes ...
If you are using an option file, make the header use [mysqlbinlog] instead of [client]. As a utility, I know [mysqlhotcopy] can be used as a group header. Please try out [mysqlbinlog] as a group header and see if it helps.
ADDITIONAL OBSERVATION
Since you are connecting to DB Server running MySQL 5.5, its mysqld will never understand --ssl-crl and --ssl-crlpath variables because they belong to MySQL 5.6.3. I guess this means you were connecting from a MySQL 5.6 machine using the mysqlbinlog for MySQL 5.6. You will not need to specify any SSL connection options if you are remote connecting for binlgogs