socket: clear error before setting a new one
socket: clear error before setting a new one

In the resolver result loop, the error might be set more than once,
and the previous error is not freed.  In debug mode, this condition is
detected, and causes an assertion failure.

cmende/libmpdclient,sl0th/libmpdclient,yusiwen/libmpdclient,cmende/libmpdclient,jagleeso/libmpdclient,jwise/libmpdclient,jwise/libmpdclient,sl0th/libmpdclient,yusiwen/libmpdclient,sl0th/libmpdclient,cmende/libmpdclient,psych0tik/libmpdclient2,jagleeso/libmpdclient,OpenInkpot-archive/iplinux-libmpdclient,psych0tik/libmpdclient2,jwise/libmpdclient,jagleeso/libmpdclient,yusiwen/libmpdclient,OpenInkpot-archive/iplinux-libmpdclient