epm-query: fix __print_suffix (skip for empty arg)

bin/epm-query

@@ -25,6 +25,7 @@ __print_with_arch_suffix()
 {
 	local pkg="$1"
 	local suffix="$2"
+	[ -n "$pkg" ] || return 1
 	# do not change if some suffix already exists
 	echo "$pkg" | grep -q "(x86-32)$" && echo "$pkg" | sed -e "s|(x86-32)$|.i686|" && return 1
 	echo "$pkg" | grep "\.x86_64$" && return 1