Bump shiro to 1.7.1

Bump shiro to 1.7.1

This patch bumps the shiro dependency, release notes are here:

https://shiro.apache.org/news.html#1.4.0-RC2-released
https://shiro.apache.org/news.html#1.4.1-released
https://shiro.apache.org/news.html#1.4.2-released
https://shiro.apache.org/news.html#1.5.0-released
https://shiro.apache.org/news.html#1.5.1-released
https://shiro.apache.org/news.html#1.5.2-released
https://shiro.apache.org/news.html#1.5.3-released
https://shiro.apache.org/news.html#1.6.0-released
https://shiro.apache.org/news.html#1.7.0-released
https://shiro.apache.org/news.html#1.7.1-released

We end up repackaging shiro to deal with class loading issues
coming it faces. Those will be cleaned up in version shiro-2,
which when we ill just revert back to using their packaging.

JIRA: AAA-188
Change-Id: Ic1d5c4243776c5cd72778c248ba5824a4acc4a91
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>