Support IPv6 proxy exceptions in OSGiHttpRoutePlanner

The code in https://github.com/apache/httpcomponents-client/blob/54900db4653d7f207477e6ee40135b88e9bcf832/httpclient-osgi/src/main/java/org/apache/http/osgi/impl/OSGiHttpRoutePlanner.java#L67 can only correctly deal with host name, domain name or IPv4 address exceptions. This is due to the fact that the inner class NetworkAddress only parses IPv4 format address specs (and only stores the address internally in an int = 32 bit) (https://github.com/apache/httpcomponents-client/blob/54900db4653d7f207477e6ee40135b88e9bcf832/httpclient-osgi/src/main/java/org/apache/http/osgi/impl/OSGiHttpRoutePlanner.java#L154-L177)