Fix getty restart loop when PTS device is gone

Patch backported from 218.

Closes: #780711

debian/changelog

@@ -4,6 +4,9 @@ systemd (215-15) UNRELEASED; urgency=medium
   * debian/systemd.{triggers,postinst}: Trigger a systemctl daemon-reload
     when init scripts are installed or removed (Closes: #766429)
 
+  [ Martin Pitt ]
+  * Fix getty restart loop when PTS device is gone. (Closes: #780711)
+
  -- Martin Pitt <mpitt@debian.org>  Wed, 08 Apr 2015 10:53:38 +0200
 
 systemd (215-14) unstable; urgency=medium

debian/patches/series

@@ -144,6 +144,7 @@ scope-make-attachment-of-initial-PIDs-a-bit-more-rob.patch
 journald-also-increase-the-SendBuffer-of-dev-log-to-.patch
 list-add-macro-for-iterating-through-a-list-an-item-.patch
 core-if-two-start-jobs-for-the-same-swap-device-node.patch
+units-make-sure-container-getty-.service-stops-resta.patch
 
 ## Debian specific patches:
 Add-back-support-for-Debian-specific-config-files.patch

debian/patches/units-make-sure-container-getty-.service-stops-resta.patch

+From: Lennart Poettering <lennart@poettering.net>
+Date: Tue, 9 Dec 2014 02:12:11 +0100
+Subject: units: make sure container-getty@.service stops restarting when the
+ pts device it is bound to is gone
+
+We only want to restart the getty as long as the pts device is still
+around. As soon as it is gone, the service should be removed to.
+
+http://lists.freedesktop.org/archives/systemd-devel/2014-December/026048.html
+---
+ units/container-getty@.service.m4.in | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/units/container-getty@.service.m4.in b/units/container-getty@.service.m4.in
+index 4f7794b..5120466 100644
+--- a/units/container-getty@.service.m4.in
++++ b/units/container-getty@.service.m4.in
+@@ -14,6 +14,7 @@ After=rc-local.service
+ )m4_dnl
+ Before=getty.target
+ IgnoreOnIsolate=yes
++ConditionPathExists=/dev/pts/%I
+ 
+ [Service]
+ ExecStart=-/sbin/agetty --noclear --keep-baud pts/%I 115200,38400,9600 $TERM