CPack: Pass volume mount name to AppleScript instead of volume name.

The problem:

The user has mounted an image named "My Image" (mounted to "/Volumes/My Image"). He/she then runs CPack to generate a new image file with the same name. When CPack mounts the image it will be mounted to "/Volumes/My Image 1". The volume name "My Image" is passed to AppleScript which will open the first image instead of the last, because "tell disk image_name" actually works with the mount point name not the volume name.

The fix:

Get the mount name from mount point path returned by hdiutil and pass it to AppleScript instead of cpack_dmg_volume_name.

Topic-rename: cpack-dmg-applescript-argv