Function app-log Write hangs when called after Close

When Eventing attempts to write a message to a function's app-log file after the file has been closed, the calling goroutine gets stuck in an infinite loop.

This bug was triggered by a recent change to log a System Event Log event as well as a message to a function's app-log file when the function is auto un-deployed due to keyspace / function scope deletion, or permission revocation.