Try to create the log directory when not present yet

[eliasp]

What does this PR do?

When the log directory does not exist yet, Salt will attempt to create it now.

What issues does this PR fix or reference?

None I know of

Previous Behavior

When the log directory (default: /var/log/salt) didn't exist, Salt simply failed:

[WARNING ] Failed to open log file, do you have permission to write to /var/log/salt/minion?

New Behavior

Salt will now attempt to create the required directory in this case:

[INFO    ] Log directory not found, trying to create it: /var/log/salt

Tests written?

No

[s0undt3ch]

I believe that if you set verify_env: true on the configuration file, that directory, with a buch o other directories, are checked for existence. If they don't exist, they are created with proper ownership and permissions....

[lorengordon]

@s0undt3ch did that actually start working again? I reported this issue back in 2015.8.0 and it's still open. I tried verify_env: True then and it didn't work...

#27063 (comment)

[s0undt3ch]

Then i guess its not fixed yet :(

[cachedout]

I suppose the question then is whether we should just try to fix verify_env or abandon it and just force that behavior. I don't want to end up merging this and then having verify_env fixed down the line and end up with divergent code paths...

[s0undt3ch]

Agreed.

[thatch45]

I am going to merge this in, given the fact that the logging facility can be changed I think that keeping log directory management local to the backend makes the most sense