move dependencies to vendor

vendor/github.com/docker/libnetwork/resolvconf/dns/resolvconf.go

@@ -0,0 +1,17 @@
+package dns
+
+import (
+	"regexp"
+)
+
+// IPLocalhost is a regex patter for localhost IP address range.
+const IPLocalhost = `((127\.([0-9]{1,3}.){2}[0-9]{1,3})|(::1))`
+
+var localhostIPRegexp = regexp.MustCompile(IPLocalhost)
+
+// IsLocalhost returns true if ip matches the localhost IP regular expression.
+// Used for determining if nameserver settings are being passed which are
+// localhost addresses
+func IsLocalhost(ip string) bool {
+	return localhostIPRegexp.MatchString(ip)
+}