fix reading of yum-sqlite repo files

[sbinet]

perhaps perusing:

• http://forensicsfromthesausagefactory.blogspot.fr/2011/04/carving-sqlite-databases-from.html
• http://forensicsfromthesausagefactory.blogspot.fr/2011/05/sqlite-pointer-maps-pages.html
• http://forensicsfromthesausagefactory.blogspot.fr/2011/05/analysis-of-record-structure-within.html
• http://forensicsfromthesausagefactory.blogspot.fr/2011/07/sqlite-overflow-pages-and-other-loose.html
• http://www.sqlite.org/fileformat.html
• http://www.sqlite.org/fileformat2.html