Fixes LOGBACK-360

[TurekBot]

The way it currently stands, this script won't run.

SQL Server doesn't support DECIMAL's of size 40.

According to this doc, the max is 38.

Changing the precision to 38 seems to solve the issue in my testing.

[TurekBot]

Thanks for your hard work on logback. Let me know if there's anything I could do to make this pull request ready to merge. Thanks!