PR for BROOKLYN-597

Hi all, Per our chat about prepping for 1.0.0 I have created https://github.com/apache/brooklyn-dist/pull/150 to remove MD5 and SHA-1 from the signing process. I've marked it Do Not Merge because I can't get the make-release-artifacts.sh to work to test this. It keeps failing on

[GitHub] [brooklyn-dist] geomacy opened a new pull request #150: BROOKLYN-597 Remove md5/sha1 - DO NOT MERGE

geomacy opened a new pull request #150: BROOKLYN-597 Remove md5/sha1 - DO NOT MERGE URL: https://github.com/apache/brooklyn-dist/pull/150 Remove MD5 and SHA-1 for [BROOKLYN-597](https://issues.apache.org/jira/projects/BROOKLYN/issues/BROOKLYN-597) Also simplifies the artifact