Just a reminder to anyone reading: there are a lot of reasons for the integrity check to exist. Generally, including files in a whitelist to bypass an annoying message of “you’re doing things wrong” is bad. The integrity check is an easy way to detect several problems that could happen in any installation.
This is a reasonable case to whitelist the app though.
Check which files are actually detected as incorrect by clicking on the link in the warning.
Alternatively I think you can also run the occ integrity check command.
This means for some reason this file got there and it is not supposed to be there. Have a look at it and see if it has any useful information and move it out of the way, that should fix it.
i don’t think that your web server / PHP should put it’s log files into the ownCloud directory. In my opinion a folder like /var/log/php is the place for this.