At some point since filelogger was added on Windows, the log hierarchy
above it changed such that a log.Printf writes to filelogger and includes
the log package's own date. But then filelogger adds another.
Rather than debug everything above and risk removing the prefix when
run by tailscaled, instead just remove the log package's prefix
very late right before we go to add the filelogger's own.
Change-Id: I9db518f42c603ef83017f74827270f124fdf5c14
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Brad Fitzpatrick