fix http proxy support in spring4

Workaround waiting Spring fix proxy support. In RequestFactory, we set a
default route planner to handle proxy.

https://jira.spring.io/browse/SPR-12335 When using
HttpComponentsClientHttpRequestFactory, setting a proxy through
RequestConfig should not be ignored
Merge branch 'spring4-http-proxy-fix' of https://github.com/Orange-OpenSource/cf-java-client into Orange-OpenSource-spring4-http-proxy-fix
Merge branch 'Orange-OpenSource-spring4-http-proxy-fix' into spring4