fix https://github.com/Neilpang/acme.sh/issues/622

acme.sh

@@ -1610,14 +1610,14 @@ _setopt() {
       __val="$(echo "$__val" | sed 's/&/\\&/g')"
     fi
     text="$(cat "$__conf")"
-    echo "$text" | sed "s|^$__opt$__sep.*$|$__opt$__sep$__val$__end|" >"$__conf"
+    printf -- "%s" "$text" | sed "s|^$__opt$__sep.*$|$__opt$__sep$__val$__end|" >"$__conf"
 
   elif grep -n "^#$__opt$__sep" "$__conf" >/dev/null; then
     if _contains "$__val" "&"; then
       __val="$(echo "$__val" | sed 's/&/\\&/g')"
     fi
     text="$(cat "$__conf")"
-    echo "$text" | sed "s|^#$__opt$__sep.*$|$__opt$__sep$__val$__end|" >"$__conf"
+    printf -- "%s" "$text" | sed "s|^#$__opt$__sep.*$|$__opt$__sep$__val$__end|" >"$__conf"
 
   else
     _debug3 APP