contrib/init: (OpenRC) quote some unquoted variables.

contrib/init/bitcoind.openrc

@@ -60,9 +60,9 @@ start_pre() {
 	"${BITCOIND_PIDDIR}"
 
 	checkpath -f \
-	-o ${BITCOIND_USER}:${BITCOIND_GROUP} \
+	-o "${BITCOIND_USER}:${BITCOIND_GROUP}" \
 	-m 0660 \
-	${BITCOIND_CONFIGFILE}
+	"${BITCOIND_CONFIGFILE}"
 
 	checkconfig || return 1
 }