boost: drop boost dependency in utilstrencodings.cpp
boost: drop boost dependency in utilstrencodings.cpp

(cherry picked from commit 352058e8b0da4ec37b2f1891716c53adc2957a02)

reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin