Reinstated two stage OSX build, and disabled part of the coverity_scan build to attempt to get it running without timeout.
Reinstated two stage OSX build, and disabled part of the coverity_scan build to attempt to get it running without timeout.

scrawl/osg,openscenegraph/osg,scrawl/osg,openscenegraph/osg,openscenegraph/osg,scrawl/osg,openscenegraph/osg,scrawl/osg