Issue title: New Spatialite Layer: failed to load SRIDS
 Issue body: Author Name: **Milena Nowotarska** (Milena Nowotarska)
Original Redmine Issue: [2632](https://issues.qgis.org/issues/2632)

Redmine category:data_provider
Assignee: Gary Sherman

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Using 'Find SRID' button I get 'Failed to load SRIDS: no such table: spatial_ref_sys' error.


 Comments: 
 Comment 0: Author Name: **Jürgen Fischer** (@jef-n)


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Not reproducable here.  Which database are you trying to use?




 Comment 1: Author Name: **Milena Nowotarska** (Milena Nowotarska)


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Rarely I read documentation, my fault. Tried to use that button before pointing to the database :)

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-  resolution  was changed from    to invalid 
-  status_id  was changed from   Open   to Closed 


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