servicemanager started property

If something starts before servicemanager does,
intelligently wait for servicemanager to start rather
than sleeping for 1s.

Bug: 239382640
Test: boot
Change-Id: Ic3df299d8b37c2caeeac4ae90402e7f5be1e7ecc
diff --git a/cmds/servicemanager/servicemanager.recovery.rc b/cmds/servicemanager/servicemanager.recovery.rc
index 067faf9..b927c01 100644
--- a/cmds/servicemanager/servicemanager.recovery.rc
+++ b/cmds/servicemanager/servicemanager.recovery.rc
@@ -1,4 +1,5 @@
 service servicemanager /system/bin/servicemanager
     disabled
     group system readproc
+    onrestart setprop servicemanager.ready false
     seclabel u:r:servicemanager:s0