Summary:
Update the LogFile class in edenfs_monitor to support log rotation when the
file size exceeds a set limit.
There is a generic API to abstract out the log rotation details. For now
I have only implemented a relatively straightforward implementation that
appends the current timestamp to the log path, and prunes old log files.
Reviewed By: chadaustin
Differential Revision: D20427310
fbshipit-source-id: f6aefc8f2fe604fdd1d6a72c3d30666612912f41