Revert 110529 - Allow chrome to handle 407 auth challenges to CONNECT requests

Revert 110529 - Allow chrome to handle 407 auth challenges to CONNECT requests
through HTTPS Proxies.  This also changes the mechanism used 
to restart HttpProxyClientSocket requests with auth.  Previously
the transport socket would be Disconnected, and then re-Connected
(which was not implemented for SSLClientSockets).  However, the 
approach was problematic in the face of, for example, ipv6.  The
new approach is to close the HttpProxyClientSocket, and request
a new socket from the pool.

Review URL: http://codereview.chromium.org/8502024

TBR=rch@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=110550