TS-4626: LogFile::close_file should not delete m_log handle
TS-4626: LogFile::close_file should not delete m_log handle

LogFile::close_file was incorrectly deleting the m_log object.
This caused potential race conditions when flushing m_log since
there aren't any locks protecting m_log accesses.

When the underlying log file on disk is deleted, it is fine to
not delete m_log. It's fine because the actual flush function
in Log::flush_thread_main checks to see if m_log is open before
doing any writes.

clearswift/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,bryancall/trafficserver,chenglongwei/trafficserver,SolidWallOfCode/trafficserver,persiaAziz/trafficserver,chenglongwei/trafficserver,chitianhao/trafficserver,chitianhao/trafficserver,davidbz/trafficserver,clearswift/trafficserver,clearswift/trafficserver,persiaAziz/trafficserver,PSUdaemon/trafficserver,pbchou/trafficserver,dyrock/trafficserver,reveller/trafficserver,PSUdaemon/trafficserver,PSUdaemon/trafficserver,rpufky/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,bryancall/trafficserver,pbchou/trafficserver,clearswift/trafficserver,reveller/trafficserver,reveller/trafficserver,clearswift/trafficserver,pbchou/trafficserver,bryancall/trafficserver,duke8253/trafficserver,reveller/trafficserver,PSUdaemon/trafficserver,rpufky/trafficserver,dyrock/trafficserver,chitianhao/trafficserver,vmamidi/trafficserver,rpufky/trafficserver,reveller/trafficserver,persiaAziz/trafficserver,persiaAziz/trafficserver,davidbz/trafficserver,dyrock/trafficserver,PSUdaemon/trafficserver,chenglongwei/trafficserver,persiaAziz/trafficserver,chenglongwei/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,rpufky/trafficserver,bryancall/trafficserver,chitianhao/trafficserver,PSUdaemon/trafficserver,chitianhao/trafficserver,chenglongwei/trafficserver,SolidWallOfCode/trafficserver,reveller/trafficserver,vmamidi/trafficserver,PSUdaemon/trafficserver,PSUdaemon/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,taoyunxing/trafficserver,rahmalik/trafficserver,clearswift/trafficserver,rahmalik/trafficserver,chenglongwei/trafficserver,rahmalik/trafficserver,bryancall/trafficserver,taoyunxing/trafficserver,chitianhao/trafficserver,rahmalik/trafficserver,rahmalik/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,rpufky/trafficserver,pbchou/trafficserver,SolidWallOfCode/trafficserver,rpufky/trafficserver,chenglongwei/trafficserver,clearswift/trafficserver,PSUdaemon/trafficserver,clearswift/trafficserver,chenglongwei/trafficserver,persiaAziz/trafficserver,taoyunxing/trafficserver,chitianhao/trafficserver,rpufky/trafficserver,rahmalik/trafficserver,taoyunxing/trafficserver,taoyunxing/trafficserver,taoyunxing/trafficserver,taoyunxing/trafficserver,rpufky/trafficserver,reveller/trafficserver,rahmalik/trafficserver,duke8253/trafficserver,davidbz/trafficserver,davidbz/trafficserver,dyrock/trafficserver,rahmalik/trafficserver,duke8253/trafficserver,duke8253/trafficserver,vmamidi/trafficserver,davidbz/trafficserver,rpufky/trafficserver,reveller/trafficserver,clearswift/trafficserver,taoyunxing/trafficserver,pbchou/trafficserver,reveller/trafficserver,rahmalik/trafficserver,pbchou/trafficserver,dyrock/trafficserver,dyrock/trafficserver,vmamidi/trafficserver,davidbz/trafficserver,taoyunxing/trafficserver,duke8253/trafficserver