Fix database-list via CLI for large # of dbs

When an instance contains more than 20 databases, only the last n-20 were being
shown when trove database-list was run. The do_database_list method wasn't
correctly tracking the output when multiple pages were present.

Change-Id: I349534735b4118f3cdd4897c36bb17c0a1fdceb1
Closes-Bug: #1246599
Merge "Fix database-list via CLI for large # of dbs"