[IMP] base_external_dbsource_mysql: Don't depend on SQLite

The amount of shared code is so insignificant, that it doesn't worth to depend on
base_external_dbsource_sqlite.

base_external_dbsource_mysql/__manifest__.py

@@ -11,7 +11,7 @@
     'website': 'https://github.com/OCA/server-backend',
     'license': 'LGPL-3',
     'depends': [
-        'base_external_dbsource_sqlite',
+        'base_external_dbsource',
     ],
     'external_dependencies': {
         'python': [