Error using `termguicolors` and guibg overrides

[lithammer]

Using the .vimrc below I get the following error during startup:

Error detected while processing function <SNR>10_load_colors[3]..<SNR>10_load_color_def[1]..<SNR>10_X:
line   17:
E254: Cannot allocate color #none
Error detected while processing function <SNR>10_load_colors[4]..<SNR>10_load_color_def[1]..<SNR>10_X:
line   17:
E254: Cannot allocate color #none
Error detected while processing function <SNR>10_load_colors[5]..<SNR>10_load_color_def[1]..<SNR>10_X:
line   17:
E254: Cannot allocate color #none
Press ENTER or type command to continue

" vim-plug
call plug#begin()
Plug 'nanotech/jellybeans.vim'
call plug#end()

if has('termguicolors') " 7.4.1799
  set termguicolors
  let g:jellybeans_overrides = {
  \    'background': { 'ctermbg': 'none', '256ctermbg': 'none', 'guibg': 'none' },
  \}
  colorscheme jellybeans
endif

Vim version 7.4-2334
jellybeans version 7a63737

[nanotech]

Thanks!