Replace return with continue in update_consensus_networkstatus_downloads

Fix for bug 9564; bugfix on 0.2.3.14-alpha.
Merge remote-tracking branch 'public/bug9564' into maint-0.2.3
Merge remote-tracking branch 'origin/maint-0.2.3' into maint-0.2.4
Merge remote-tracking branch 'origin/maint-0.2.4'