update_databases assumes a populated databases.json

If this file is empty, it will not generate a proper new one.

/cc @twk3

created branch 2774-update_databases-assumes-a-populated-databases-json

mentioned in merge request !1924 (merged)

mentioned in commit 1623525e

closed via merge request !1924 (merged)

mentioned in commit fa938776

mentioned in commit 7c9e288b

mentioned in commit 5a749b72

mentioned in commit 6b7a0226