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.rc b/cmds/servicemanager/servicemanager.rc
index e5d689f..6b35265 100644
--- a/cmds/servicemanager/servicemanager.rc
+++ b/cmds/servicemanager/servicemanager.rc
@@ -3,6 +3,7 @@
     user system
     group system readproc
     critical
+    onrestart setprop servicemanager.ready false
     onrestart restart apexd
     onrestart restart audioserver
     onrestart restart gatekeeperd