Yes it is extremely annoying that one cannot remove the Boot Camp partition entry on the Virtual Machine Library without going through some hoops and jumps...

If you do the following this will stop the Boot Camp partition entry from showing on the Virtual Machine Library...

1. Close Fusion

2. In a Terminal (/Applications/Utilities/Terminal) copy and paste the following command, as is, and then press Enter and type in your password then press Enter.

sudo mv "/Library/Application Support/VMware Fusion/vmware-rawdiskCreator" "/Library/Application Support/VMware Fusion/vmware-rawdiskCreator.bak"

3. Open Fusion and then ctrl-click the Boot Camp partition entry on the Virtual Machine Library and select Delete.

Note: If you have Imported the Boot Camp partition as a normal file based Virtual Machine you could have a Boot Camp partition entry on the Virtual Machine Library that you do not want to delete so before deleting the Boot Camp partition entry on the Virtual Machine Library you can ctrl-click the Boot Camp partition entry on the Virtual Machine Library and select Show in Finder and then make sure this is the one in your "/Users/${USER}/Library/Application Support/VMware Fusion/Virtual Machines/Boot Camp" folder before removing it from the Virtual Machine Library.

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To restore the Boot Camp partition entry on the Virtual Machine Library...

1. Close Fusion

2. In a Terminal (/Applications/Utilities/Terminal) copy and paste the following command, as is, and then press Enter and type in your password then press Enter.

sudo mv "/Library/Application Support/VMware Fusion/vmware-rawdiskCreator.bak" "/Library/Application Support/VMware Fusion/vmware-rawdiskCreator"

3. Open Fusion

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Note: Make sure you copy and paste the entire command line as it may wrap on the screen. Also while I am using the .bak extension in this example the vmware-rawdiskCreator executable name only need to me changed by one character in order for it not to play a part in enumerating the Boot Camp partition to show on the Virtual Machine Library. Renaming the vmware-rawdiskCreator executable should not have any ill effect under normal circumstance if all your wanting to do is to keep the Boot Camp partition entry from appearing on the Virtual Machine Library however if you need to use he vmware-rawdiskCreator executable in the future from the command line to create a Raw Disk Mapping then remember you have renamed it.