[lib] util: fix invalid free() introduced in last change
[lib] util: fix invalid free() introduced in last change

dtebbs/picocoin,mezzovide/picocoin,dtebbs/picocoin,mezzovide/picocoin,01BTC10/picocoin,mezzovide/picocoin,01BTC10/picocoin,jl777/picocoin,favioflamingo/picocoin,jl777/picocoin,favioflamingo/picocoin,jl777/picocoin,01BTC10/picocoin,dtebbs/picocoin