NERDTreePatternMatchHighlightColor works, but with error "Cannot allocate color"

[vitaly-zdanevich]

My config for your plugin:

let g:NERDTreeFileExtensionHighlightFullName = 1
let g:NERDTreeExactMatchHighlightFullName = 1
let g:NERDTreePatternMatchHighlightFullName = 1

let g:NERDTreePatternMatchHighlightColor = {} " this line is needed to avoid error
let g:NERDTreePatternMatchHighlightColor['.*_test\.go$'] = 'f00'