Revert "Update ol3 to include https://github.com/openlayers/ol3/pull/925"

This reverts commit 93b4ef88f8ca9e571f11c08680beea3f33a30f69.
Merge pull request #358 from geoadmin/fix_revertol

Revert "Update ol3 to include https://github.com/openlayers/ol3/pull/925...