Re-add newline to error() messages
Re-add newline to error() messages

As reported by @Subo1978, error messages don't have a trailing newline
anymore after commit b77dfdc9. Add back this newline.

syscoin/syscoin,Infernoman/crowncoin,domob1812/crowncoin,Crowndev/crowncoin,syscoin/syscoin,Crowndev/crowncoin,domob1812/crowncoin,Infernoman/crowncoin,Crowndev/crowncoin,syscoin/syscoin,Infernoman/crowncoin,domob1812/crowncoin,syscoin/syscoin,Infernoman/crowncoin,domob1812/crowncoin,Crowndev/crowncoin,Infernoman/crowncoin,Infernoman/crowncoin,Crowndev/crowncoin,syscoin/syscoin,syscoin/syscoin,domob1812/crowncoin,domob1812/crowncoin,Crowndev/crowncoin,syscoin/syscoin,syscoin/syscoin