Release version 215-17+deb8u4 to stable

debian/changelog

-systemd (215-17+deb8u4) UNRELEASED; urgency=medium
+systemd (215-17+deb8u4) stable; urgency=medium
 
   [ Martin Pitt ]
   * debian/udev.prerm: Add missing "deconfigure" action. (Closes: #809744)
@@ -19,7 +19,7 @@ systemd (215-17+deb8u4) UNRELEASED; urgency=medium
   * Fix --network-interface in systemd-nspawn to not fail when modifying an
     existing link. (Closes: #813696)
 
- -- Martin Pitt <mpitt@debian.org>  Sat, 09 Jan 2016 16:24:05 +0100
+ -- Michael Biebl <biebl@debian.org>  Thu, 03 Mar 2016 19:51:22 +0100
 
 systemd (215-17+deb8u3) stable; urgency=medium