Make checkstop service wait for system manager

Don't start the host checkstop reboot service until the
system manager service has been started.

Resolves openbmc/openbmc#603

Change-Id: Ideca52faaa2d7347c66fa719dc4b8f8f6b24aedf
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/common/recipes-phosphor/chassis/obmc-hostcheckstop/org.openbmc.control.Checkstop@.service b/common/recipes-phosphor/chassis/obmc-hostcheckstop/org.openbmc.control.Checkstop@.service
index 3b169c5..d5fea67 100644
--- a/common/recipes-phosphor/chassis/obmc-hostcheckstop/org.openbmc.control.Checkstop@.service
+++ b/common/recipes-phosphor/chassis/obmc-hostcheckstop/org.openbmc.control.Checkstop@.service
@@ -1,5 +1,7 @@
 [Unit]
 Description=Phosphor Host%i Checkstop Monitor
+Wants=mapper-wait@-org-openbmc-managers-System.service
+After=mapper-wait@-org-openbmc-managers-System.service
 
 [Service]
 Restart=always