[FIXED JENKINS-6795] Maven agent needs a fix for the 'hardcoded' socket connection to localhost, perhaps a fallback mechanism when it fails to connect through the loopback interface can solve this pesky issue?

It actually contains one hunk that is necessary, but I'll merge it from
the 1.408 branch.

This reverts commit 6523693e.

This reverts commit 5c1007dd.

This reverts commit bd818192.

This reverts commit a903b3ab.

This reverts commit eb7292e1.

Conflicts:
	changelog.html

a903b3ab

identical copies into WEB-INF/lib.

As a result, which one gets chosen is up to the file system /
classloader, and hence we failed to catch it sooner.