[autotest] log master-ssh process `lsof` after unexpected death

This CL adds more detailed logging after unexpected master-ssh death, to
make it hopefully easier to solve The Case Of The Missing Socket File.

BUG=chromium:305641
TEST=None

Change-Id: I736232a6d79973445a846c39845df8459ea7350a
Reviewed-on: https://chromium-review.googlesource.com/172586
Reviewed-by: Aviv Keshet <[email protected]>
Commit-Queue: Aviv Keshet <[email protected]>
Tested-by: Aviv Keshet <[email protected]>
1 file changed