ruby2.1 - security update

It was discovered that the Ruby OpenSSL extension, part of the interpreter
for the Ruby language, did not properly implement hostname matching, in
violation of RFC 6125. This could allow remote attackers to perform a
man-in-the-middle attack via crafted SSL certificates.

For the stable distribution (jessie), this problem has been fixed in
version 2.1.5-2+deb8u1.

For the testing distribution (stretch), this problem has been fixed in
version 2.1.5-3.

For the unstable distribution (sid), this problem has been fixed in
version 2.1.5-3.

We recommend that you upgrade your ruby2.1 packages.