reproducible Debian: Mark cbxi4a online.

Added some additional delays in the boot process which might reduce
future problems.

jenkins-home/offline_nodes

@@ -14,8 +14,6 @@
 # Also see https://pad.sfconservancy.org/p/rb-build-nodes-keep
 
 # investigation needed
-## tried power-cycling several times:
-cbxi4a-armhf-rb.debian.net
 
 # Down here nodes are automatically added by the maintenance job when they have
 # been failing their health check or maintenance job for too long.