Race in TERM handling in glideinFrontendElement
This is related to #4436. Talking to Alison made me realize we may also trigger a race from time to time in the frontend as well -- she said
there were frequently orphaned glideinFrontendElement processes after trying to stop her frontend that hung around for 10 minutes before ceasing.
We should deregister the sighandlers for the children here too and just let SIGTERM kill them.