Remove unused function `mask_features`
Remove unused function `mask_features`

Signed-off-by: Rob Hoes <8783b3376fb07d39edffc8d7da68a6de3874a7e6@citrix.com>

Chunjie/xcp-idl,xapi-project/message-switch,johnelse/xcp-idl,xapi-project/message-switch,euanh/xcp-idl,xapi-project/message-switch