ssl-proxies: Fix several race conditions

In particular the race in CertificateIOUtil has caused signing policies
be registered with the wrong hash. This in turn causes certificates
from the corresponding CA to be rejected.

(cherry picked from commit 1a0952b493a62e30dfe84937ec76cca00a8b6095)
Merge pull request #96 from gbehrmann/fix/v2.0/races-signing-policy

ssl-proxies: Fix several race conditions
Fix SCM URL per newer version of maven.
Try newer version of maven release to see if it clears up the git issues.
Attempt fix of SCM URL for maven-release-plugin 2.2.

Seems to want the older-style of git URL.
[maven-release-plugin] prepare release v2.0.6
Include sonatype fixes from 2.0.5.
gss: Empty application data messages must not trigger end-of-stream

Addresses an issue in which SSL application data messages with zero
payload are misinterpreted as end-of-stream. This bug causes JGlobus
to fail with more recent versions of curl.
Merge pull request #99 from gbehrmann/fix/v2.0/empty-ssl-message

gss: Empty application data messages must not trigger end-of-stream
ssl-proxies: Add information about chain to CertPathValidationException

CertPathValidationException has fields to capture the CertPath and
certificate index that triggered the validation failure. This allows
an application to provide more information about the failure to the
user. Yet, JGlobus didn't fill in these fields of the exception,
meaning that the user would not be offered any information beyond
a simple error message saying that the certificate was rejected.

This patch adds the missing information. An application still has to
detect the exception in the exception cause chain and present it to
the user in some form.
(cherry picked from commit df5c4f845bf2da7e15a075aa187f211014542827)
Merge pull request #100 from gbehrmann/fix/v2.0/certpathvalidation_includes_certpath

ssl-proxies: Add information about chain to CertPathValidationException