Use the path to the database instead of the db object.

[jordansissel]

Fixes #5

[bemaru]

I'm manually apply this fix, but it's inconvenient.
C:\logstash-7.11.1\vendor\bundle\jruby\2.5.0\gems\logstash-input-sqlite-3.0.4\lib\logstash\inputs\sqlite.rb

Please accept MR.

[tcrensink]

any reason not to commit this? see: 98498da

[garrett-partenza-us]

Works for me as well.