Change: enhances dynamic resolve functionality

*) support fail timeout and fallback action
*) support using all IP addresses in dns response
*) support using stale dns result as a fallback ation

Signed-off-by: paulyang <y_y@neusoft.com>
test case for dynamic resolve

adjust dynamic resolve test case to match new enhancements

Signed-off-by: paulyang <y_y@neusoft.com>
Bugfix: in dynamic resolve

*) reinit load balancer
*) don't decrease reference for original upstream server conf

Signed-off-by: paulyang <y_y@neusoft.com>
Change: in dynamic resolve functionality

move uscf->peer.init into upstream_reinit handler

Signed-off-by: paulyang <y_y@neusoft.com>
Change: revert test cases of load balancer

avoid running dynamic resolve cases in load balancer, need to re-design
the test cases.

Signed-off-by: paulyang <y_y@neusoft.com>
Merge branch 'dyn-opti-simple'