[FIX] maps: Cope with zoom levels greater than can be shown in OpenStreetMap, the default layer (was causing zoom to be reset to 3 on tracker items)
Should be done more programmatically, rather than using hard coded layer names (one day)

git-svn-id: file:///var/local/code.tiki.org/tikisvn/trunk@47414 b456876b-0849-0410-b77d-98878d47e9d5