Fix PeerConnectionInterfaceTest_StartAndStopLoggingAfterPeerConnectionClosed

PeerConnectionInterfaceTest_StartAndStopLoggingAfterPeerConnectionClosed was using an invalid file, then checking that StartRtcEventLog returns false. Such a test might return a false positive, since StartRtcEventLog might fail because it was given an invalid file, rather than because the PC was already closed.


Bug: webrtc:8111
Change-Id: I844eb3b948b1406bb6f5cc63928eb26f0fb7b694
Reviewed-on: https://webrtc-review.googlesource.com/8541
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Commit-Queue: Elad Alon <eladalon@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20253}