led-manager: start led-manager after object mapper

The new commit in led-manager may make a call to object mapper
in some case as part of its start and hence putting the dependency

Change-Id: Ic6ee8ef1048c1001af85f10e0e2a3deb8141e083
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/recipes-phosphor/leds/phosphor-led-manager/xyz.openbmc_project.LED.GroupManager.service b/recipes-phosphor/leds/phosphor-led-manager/xyz.openbmc_project.LED.GroupManager.service
index 8e852a4..5e361a3 100644
--- a/recipes-phosphor/leds/phosphor-led-manager/xyz.openbmc_project.LED.GroupManager.service
+++ b/recipes-phosphor/leds/phosphor-led-manager/xyz.openbmc_project.LED.GroupManager.service
@@ -1,6 +1,8 @@
 [Unit]
 Description=Phosphor LED Group Management Daemon
 Before=mapper-wait@-xyz-openbmc_project-led-groups.service
+Wants=obmc-mapper.target
+After=obmc-mapper.target
 
 [Service]
 Restart=always