Re-enable osgWrappers/deprecated-dotosg excluding osgFX

Dumping the scene graph from flightgear results in an empty file, so revert commit 83548845 ("Even more disabled stuff") which disabled building of deprecated serializers (osgWrappers/deprecated-dotosg).

We also need to disable deprecated-dotosg/osgFX to avoid link errors as we don't build osgFX since commit b530fd07 ("Do not compile osgFX").

Fixes: 83548845 ("Even more disabled stuff")