Make sure 'LibGMT.log_to_file' removes the file even if an exception occurs

[leouieda]

Right now, it doesn't check that the log file is deleted if there was an error in setting the logging or an exception occurs inside the with block. I would guess that it isn't. It be good to implement a test to make sure the file is deleted.

[seisman]

It seems this issue can be closed since #188 removed the log_to_file function.

[leouieda]

👍