Add conditional so globe.cpp builds with older versions of Marble

In commit 7f3b487c77c7 ("Restore the previous globe zoom level after
showing dive without GPS") I was a bit too aggressive in replacing a
deprecated API function - people still need to be able to compile against
Marble versions older than 4.10.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>